Light and matter in sync

Contributed by Saar Nehemia and Ido Kaminer – Technion, Israel Institute of Technology.

In 1934, Pavel Cherenkov discovered that when charged particles surpass the speed of light in matter, they generate an electromagnetic shockwave. A well-known analogue for this phenomenon is a sonic boom – shockwaves of sound generated when jet planes surpass the speed of sound in air. This new understanding of light–matter interactions led Cherenkov to share the 1958 Nobel Prize in Physics with Ilya Frank and Igor Tamm for his experiment and their theory. The Vavilov–Cherenkov effect has been studied extensively since then and besides being of fundamental science importance, it has led to applications in particle identification, medical imaging, quantum cascade lasers, optical frequency combs, laser-driven particle acceleration, and other areas of nonlinear optics and nanophotonics

In 2020, our paper in Nature Physics demonstrated an experimental signature of a quantum Cherenkov effect. In this post, we take you behind the scenes of our experiment.

The quantum Cherenkov effect

The Cherenkov interaction and analogous effects were mainly studied in the context of classical physics; however, some scientists were interested in their quantum description. The first to study the quantum nature of the Cherenkov effect were Ginzburg and Sokolov in 1940. The conclusion from their work was that quantum corrections to the Cherenkov effect are negligible and irrelevant. In a later paper from 1996, Ginzburg even states that “In 1940, L D Landau told about my work stated that it was of no interest. It follows from the above, that he was fully justified in drawing this conclusion, and his comment hit the mark as was usual with his criticism”. For many years, this statement and related beliefs created a conception that kept scientists away from studying the quantum Cherenkov effect.

A series of theoretical papers from the past 5 years revisited the quantum Cherenkov effect and ignited a new interest in its consequences, starting with our theoretical paper from 2016. These papers predicted interesting consequences for a quantum treatment of Cherenkov-type effects and envisioned that modern experimental capabilities and advances in electron microscopy and in quantum optics could lead to the demonstration of quantum Cherenkov-type phenomena.

Over the last couple of years, other scientists began to predict similar theoretical features in related effects, such as the Smith-Purcell effect (see work by Talebi, Gover, Arie, Polman, and Garcia de Abajo). All these effects can be considered as Cherenkov-type because they all share the same underlying principle: an enhanced interaction between a charged particle and light that occurs when the velocity of the particle matched the phase velocity of light – also termed phase-matched particle–light interaction. These theoretical findings increased the general interest in building an experiment to test these theoretical predictions.

Illustration of the electron-laser interaction, inspired by Pink Floyd’s cover art of Dark Side of the Moon. Each electron is coherently split into a wide energy spectrum (rainbow). The laser light (red) has to be coupled at a precise angle to achieve the strong interaction, in which the electron simultaneously absorbs and emits hundreds of photons from the laser.

Morgan H. Lynch and Saar Nehemia, Technion AdQuanta lab.

There exist three types of quantum effects that can occur in phase-matched particle–light interactions.

  1. Recoil corrections due to the quantization of the electromagnetic field. The emission occurs in quantized packets, creating a deviation from classical theories of radiation emission. This effect was first analyzed in 1940 by Ginzburg and Sokolov, in the context of the Cherenkov effect.
  2. Intrinsic changes to both the charge dynamics and the emission properties due to higher-order processes in QED. These effects include photon re-absorption that causes an electron mass correction (analogous to Lamb shift in renormalization theory), all being effects that cannot be explained classically.
  3. Phenomena due to the quantum wave nature of the charged particle, with features that cannot be explained by a classical point-charge description, such as the emergence of discrete energy peaks in the electron energy distribution. This is what we measured in 2020.

Our paper

In our recent work, we measured the third type of the quantum effects described above. To demonstrate the Cherenkov-type interaction, we launched a laser pulse through an optical medium (see prism, below) to synchronize its velocity with a highly-collimated electron beam passing nearby. Using a very accurate electron energy spectrometer (as used in the EELS technique), we measured the electron energy distribution and revealed the discrete energy peaks discussed above. The longitudinal profile of the electron wavefunction altered the interaction. Analogous quantum corrections also arise from transverse features in the electron wavefunction, as its orbital angular momentum (OAM) or its transverse spatial profile.

An optical microscope image of the prism used in the experiment. This 0.5 mm prism was attached to a 3 mm surface (darker background) with a square hole (center of image). The prism alignment was extremely precise to ensure that the electrons interact resonantly with the light in the prism. These electrons then pass through the square hole at the center of the surface.

The Technion AdQuanta lab.

Our experiment demonstrated a Cherenkov-type interaction between light waves and an electron wavefunction: the Cherenkov conditions are satisfied between an electron pulse and an incoming laser pulse that stimulates the interaction. This stimulated-Cherenkov effect is also known as the inverse-Cherenkov effect. The excitation laser pulse interacts with the electron at the Cherenkov angle (the same angle at which the radiation is emitted in the Cherenkov effect), resulting in a phase-matching between the electron and the laser light that leads to their strong interaction – causing both energy gain and energy loss – occurring simultaneously by each individual electron. In our experiment, this interaction is sustained over hundreds of wavelengths, causing the electron to become a coherent superposition of hundreds of energy levels.

Our setup is based on the ultrafast transmission electron microscope (UTEM), which utilizes femtosecond lasers for pump probe experiments. The microscope offers several degrees of freedom to measure the interactions between light and free electrons: controlling the delay between the light (“pump”) and the electron (“probe”), in addition to the light wavelength and polarization. The microscope allows us to control the electron wavefunction in space and time through its interaction with the laser.

Illustration of the UTEM set-up, showing the grazing-angle interaction with a prism.

Dahan et al. Nat. Phys. 16 1123–1131(2020)

Our Cherenkov experiment required a unique configuration that has never been achieved in a UTEM system, or in any transmission electron microscope: we needed to align the electron beam to graze the surface of our prism over 500 microns, while remaining at a distance of just 100 nanometers from the surface. To understand how complex this achievement is, consider that even samples that are 10,000 times thinner (nanometer scale, about the size of the corona virus or a couple of DNA strands) are considered quite thick in transmission electron microscopy.

To explain our results, we used the theory that was originally developed for a technique called photon-induced nearfield electron microscopy (PINEM), and extended it to describe our grazing-angle interaction. While all previous PINEM experiments dealt with localized interactions (in which the electron-light interaction spans over a single light wavelength or much below), our grazing angle experiment enabled the electron-light interaction to extend over hundreds of field cycles and hundreds of wavelengths. By satisfying energy–momentum matching over a long interaction distance and a prolonged interaction duration, the interactions become stronger by orders of magnitude compared to localized interactions – this opens the way to creating strong and ultrastrong coupling phenomena with free electrons.

Going back to the types of quantum effects that can arise in electron-light interactions, the PINEM interactions (see work by Carbone, Ropers and others) can be seen as an occurrence of the quantum effect of the third type – since it depends on the electron wavefunction. However, PINEM interactions before our work did not reach the Cherenkov-type interaction because they relied on localized fields (interestingly, even the acronym PINEM includes the word “nearfield”, although other types of fields can also create the effect).

The Cherenkov effect is only one example of phased-matched particle–light interactions. The energy–momentum phase-matching condition that is famously found in the Cherenkov effect also occurs in the Smith-Purcell effect, their inverse effects and a wide range of electron–light interactions that satisfy similar phase-matching conditions.

Looking Ahead

Simulation of the electron-laser interaction. The laser light (red-blue wave) interacts with the electron wavefunction (elongated sphere). This setup assures that the electron exchanges energy with the laser in a resonant manner – achieving the precise conditions of the Cherenkov effect.

Dahan et al. Nat. Phys. 16 1123–1131(2020)

In another recent study by our group in 2020, published in Nature, we measured the interaction of free electrons with light captured inside a photonic cavity (also measured at the same time here). Looking ahead, we envision combining the Cherenkov phase-matched interaction with an elongated photonic cavity as a route to achieving efficient electron-photon interactions. The cavity will channel emitted photons that can then be resonantly reabsorbed by the elongated electron, creating a strongly-coupled electron–photon hybrid. This hybrid will enable the exploration of extreme conditions such as single-electron–single-photon interactions, which can serve as a novel mechanism for number-resolved single photons detection.

Reaching this regime of physics would open previously unknown processes like free-electron Lamb shifts, controllable free-electron mass renormalizations, and potentially even cavity-mediated Cooper pairs of free electrons. These exciting prospects rely on the quantum interaction of free electrons with photons that are dressed by their optical environment – which enables the Cherenkov effect and many other future ideas.

 

 

 

Announcing winners of Nature India Photo Contest 2020

After a week of open voting for favourites, and selection by a global jury of Nature Research editors and designers, we are ready to roll out the verdict of the Nature India Photo Contest 2020.

The photographs have been judged for their adherence to this year’s theme ‘pandemic’, for their creative thinking, quality and print worthiness.

The winner of the Nature India photo contest 2020 is:

Partha Paul

for his powerful composition ‘Sampling immunity’, which has a child in the middle of the COVID-19 triangle, and symbols of the virus and the protective mother on either sides.

In Partha Paul’s words: “A health worker collects blood sample from a child in Kolkata, West Bengal as part of a sero survey to determine prevalence of SARS-CoV-2 in populations. In the middle of the COVID-19 pandemic, these surveys were conducted to determine what part of a population had developed antibodies. This was the first day of antibody tests in Kolkata’s Belgachia slum, one of the worst affected by COVID-19. This child, seen here with her mother, came from a ‘red zone’ where the government had enforced maximum containment measures.”

The second prize goes to:

Amitava Chandra

for his striking picture ‘Immersive innovation’, which makes a beautiful juxtaposition of faiths — of religion and of science.

Amitava Chandra says, “The annual Durga Puja festivities end with the immersion of the gods’ idols in river Hooghly, a tributary of the Ganges. Every year thousands of people take part in the idol immersion processions. Following COVID-19 restrictions, the festival organising committees created temporary water bodies to ‘immerse’ the clay-made idols by dissolving them with high power water jets, like in this picture taken at the Tridhara Sanmilani Puja Pandal, Kolkata on 26 October 2020. The benefits were two-fold – no processions, and no pollution of the Ganges’ waters.”

The third prize winner is:

Kaushik Dutta

for his imaginative picture ‘Migrant trouble’, which captures in the eyes of a child the threat of the pandemic symbolised by the ‘gun’ of the thermometer.

“Sending millions of migrant workers from across Indian cities back to their hometowns became a herculean task for the Indian government during the COVID-19 lockdown. This little girl boarded a train of migrant workers hoping to return home with her family. Unaware of the pandemic and what it means, she looks on with amazement at a healthcare worker in protective gear measuring her temperature with a thermal gun at the Howrah train station in West Bengal, India.”

Many congratulations to the winners!

The winners of the Nature India photo contest 2020 will get cash awards ($350, $250 and $200 respectively). They will receive a copy of the Nature India Annual Volume 2020 and a bag of goodies from Nature Research. One of the winning entries also stands a chance of being featured on the cover of a forthcoming print publication.

A special mention for all our other finalists (Deepak KumbharNila Nandi, Sandip Sarkar, Aishwarya Nilakhe, Sourav KarmakarAnindya Chattopadhyay), whose pictures portrayed various aspects of the pandemic’s socio-cultural impact. These pictures will linger in our memories for a long time.

Nature India Photo Contest 2020: Finalist #10

Marking the end of the shortlist, we unveil finalist #10 in the Nature India Photo Contest 2020 themed ‘pandemic’:

Kaushik Dutta, Kolkata, West Bengal

Photo Caption: Migrant trouble

“Sending millions of migrant workers from across Indian cities back to their hometowns became a herculean task for the Indian government during the COVID-19 lockdown. This little girl boarded a train of migrant workers hoping to return home with her family. Unaware of the pandemic and what it means, she looks on with amazement at a healthcare worker in protective gear measuring her temperature with a thermal gun at the Howrah train station in West Bengal, India.” — Kaushik Dutta

Congratulations Kaushik for for your second entry making it to the top 10 shortlist of the Nature India Photo Contest!

That brings us to the final picture in the 2020 Nature India Photo Contest shortlist. Watch this space for the announcement of the winners in the coming weeks.

The Nature India editorial and design teams have chosen ten stunning finalists, that will be rolled out (in no particular order of merit) over the next few days. These entries have been judged for novelty, creativity, quality and print worthiness. Nature India’s final decision to chose the winner will be partly influenced by the engagement and reception these pictures receive here at the Indigenus blog, on Twitter and on Facebook. To give all finalists a fair chance, we will consider the social media engagement each picture gets only during the first seven days of its announcement. The final results will be announced sometime in early February 2021.

Watch this space as we announce the other finalists in the coming days. Like, share and comment on your favourite photos on Twitter and on Facebook with the hashtag #NatureIndphoto to make them win.

The winning pictures will get cash prizes worth $350, $250 and $200 respectively. The top 10 finalists will be featured here, on Nature India’s blog Indigenus and in our subsequent annual issue.

The winner and runners-up will also receive a copy of the Nature India Annual Volume 2020 and a bag of Nature Research goodies. Winning entries stand a chance of being featured on the cover of one of our forthcoming print publications.

 

Nature India Photo Contest 2020: Finalist #9

Here’s finalist #9 in the Nature India Photo Contest 2020 themed ‘pandemic’:

Nila Nandi, Kolkata, West Bengal

Photo Caption: Sole congregation

“A man offers namaz alone at the famous Lodhi Gardens in Delhi following restrictions on religious congregations under the COVID-19 social distancing protocol.” — Nila Nandi

Congratulations Nila for making top 10 shortlist of Nature India Photo Contest!

The Nature India editorial and design teams have chosen ten stunning finalists, that will be rolled out (in no particular order of merit) over the next few days. These entries have been judged for novelty, creativity, quality and print worthiness. Nature India’s final decision to chose the winner will be partly influenced by the engagement and reception these pictures receive here at the Indigenus blog, on Twitter and on Facebook. To give all finalists a fair chance, we will consider the social media engagement each picture gets only during the first seven days of its announcement. The final results will be announced sometime in early February 2021.

Watch this space as we announce the other finalists in the coming days. Like, share and comment on your favourite photos on Twitter and on Facebook with the hashtag #NatureIndphoto to make them win.

The winning pictures will get cash prizes worth $350, $250 and $200 respectively. The top 10 finalists will be featured here, on Nature India’s blog Indigenus and in our subsequent annual issue.

The winner and runners-up will also receive a copy of the Nature India Annual Volume 2020 and a bag of Nature Research goodies. Winning entries stand a chance of being featured on the cover of one of our forthcoming print publications.

Nature India Photo Contest 2020: Finalist #8

And now it’s time for the finalist #8 in the Nature India Photo Contest 2020 themed ‘pandemic’:

Sandip Sarkar, Kolkata, West Bengal

Photo Caption: Safety is in fashion

“As the World Health Organisation deemed cloth masks fit for use, apparel designers across the world made masks that would appeal to youngsters and encourage them to wear the simple protective gear to check the spread of SARS-CoV-2. This young woman was happy to be clicked with her mask on, as she stepped out of home during the festival season, making a fashion statement alongside practicing safety.” — Sandip Sarkar

Congratulations Sandip for making it to the top 10 of the Nature India Photo Contest!

The Nature India editorial and design teams have chosen ten stunning finalists, that will be rolled out (in no particular order of merit) over the next few days. These entries have been judged for novelty, creativity, quality and print worthiness. Nature India’s final decision to chose the winner will be partly influenced by the engagement and reception these pictures receive here at the Indigenus blog, on Twitter and on Facebook. To give all finalists a fair chance, we will consider the social media engagement each picture gets only during the first seven days of its announcement. The final results will be announced sometime in early February 2021.

Watch this space as we announce the other finalists in the coming days. Like, share and comment on your favourite photos on Twitter and on Facebook with the hashtag #NatureIndphoto to make them win.

The winning pictures will get cash prizes worth $350, $250 and $200 respectively. The top 10 finalists will be featured here, on Nature India’s blog Indigenus and in our subsequent annual issue.

The winner and runners-up will also receive a copy of the Nature India Annual Volume 2020 and a bag of Nature Research goodies. Winning entries stand a chance of being featured on the cover of one of our forthcoming print publications.

Nature India Photo Contest 2020: Finalist #7

And it’s time for finalist #7 in the Nature India Photo Contest 2020 themed ‘pandemic’:

Aishwarya Nilakhe, New Delhi

Photo Caption: All-pervasive pandemic

“A researcher at the National Institute of Immunology in New Delhi, picks up a forgotten hobby to relieve the mental stress of the pandemic but ends up painting the very malady he is trying to get his mind away from. Painting by Owais Rashid Hakeim.” — Aishwarya Nilakhe

Many congratulations Aishwarya for featuring in the top 10 of the Nature India Photo Contest!

The Nature India editorial and design teams have chosen ten stunning finalists, that will be rolled out (in no particular order of merit) over the next few days. These entries have been judged for novelty, creativity, quality and print worthiness. Nature India’s final decision to chose the winner will be partly influenced by the engagement and reception these pictures receive here at the Indigenus blog, on Twitter and on Facebook. To give all finalists a fair chance, we will consider the social media engagement each picture gets only during the first seven days of its announcement. The final results will be announced sometime in early February 2021.

Watch this space as we announce the other finalists in the coming days. Like, share and comment on your favourite photos on Twitter and on Facebook with the hashtag #NatureIndphoto to make them win.

The winning pictures will get cash prizes worth $350, $250 and $200 respectively. The top 10 finalists will be featured here, on Nature India’s blog Indigenus and in our subsequent annual issue.

The winner and runners-up will also receive a copy of the Nature India Annual Volume 2020 and a bag of Nature Research goodies. Winning entries stand a chance of being featured on the cover of one of our forthcoming print publications.

Publishing metrics and agricultural science

Having achieved an H-index of 100, Rajeev Varshney* explains what the metric means in scientific publishing and why it is a milestone, especially in an agricultural scientist’s life.

H-index is an author-level metric that measures both productivity and citation impact of an author’s publications across the global scientific community. It is calculated by counting the number of publications in which an author has been cited by other authors. H-index 100 means each of the latest 100 of the author’s papers have been cited at least 100 times.

Opinions vary on these metrics and the number of citations is not the only way to measure scientific impact. But it certainly is one of the many metrics that recognise scientists’ publishing lives, and in turn, their science. Research publications are a great way to share the latest advancements in science with the global community. They also help reduce redundancy or duplication in research while directly or indirectly saving the valuable time and effort of the scientific community as also taxpayers’ money.

Generally speaking, medical science generates more research innovations that are used by different biological disciplines, including agricultural sciences. As a result, citations in medical science research are higher than agricultural science publications. When agricultural science publications have high citations, it does indicate that the research is making an impact in advancing science. The milestone of 100 h-index is a recognition of the high-quality science at ICRISAT with colleagues and partners from across the globe.

The metric that matters even more

The real battle that agricultural science should wage is against hunger, food insecurity and malnutrition. Scientists in the same discipline anywhere can learn from the latest research and take it forward to address issues of smallholder farmers while advancing the cause of scientific research for global good.

As scientists, we believe in every study we conduct irrespective of the results we get. Some of the research we conducted with a large number of global partners has an edge over the others because of massive learnings from the multidisciplinary scientists involved. For example, our genome sequencing work of 429 chickpea lines was a collaboration of 39 scientists from 21 research institutes across 45 countries. It tapped next-generation sequencing (NGS) technology to better understand the genetic architecture, centre of origin, migration route as well as genetic loci for agronomic traits in chickpea. This study1 with several brilliant minds from across the world offered much learning for me.

Chickpea crop improvement has been a key area of Varshney’s research.

There is a great sense of satisfaction when the upstream research we conduct delivers results in farmers’ fields in addition to advancing the cause of science for global good. As a genomics scientist, I provide research outputs for breeding programmes that develop improved crops.

ICRISAT’s collaborative work on genomics-assisted breeding helped develop and release the first set of products in 2019. There were three high yielding, wilt resistant varieties of chickpea2, 3 and two high-oleic varieties of groundnut4. The Ethiopian Institute of Agricultural Research also released a high-yielding chickpea variety5. The groundnut varieties were among the 17 biofortified crops dedicated to India on World Food Day 2020.

My efforts in genomics-assisted breeding will continue with an aim to accelerate the replacement of older crop varieties to help smallholding farmers improve their income and ensure better nutrition and health for the society.

(*Rajeev Varshney is Research Program Director, Genetic Gains and Director, Center of Excellence in Genomics & Systems Biology at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, India.)

Nature India Photo Contest 2020: Finalist #6

Here is finalist #6 in the Nature India Photo Contest 2020 themed ‘pandemic’:

Partha Paul, Kolkata, West Bengal

Photo Caption: Sampling immunity

“A health worker collects blood sample from a child in Kolkata, West Bengal as part of a sero survey to determine prevalence of SARS-CoV-2 in populations. In the middle of the COVID-19 pandemic, these surveys were conducted to determine what part of a population had developed antibodies. This was the first day of antibody tests in Kolkata’s Belgachia slum, one of the worst affected by COVID-19. This child, seen here with her mother, came from a ‘red zone’ where the government had enforced maximum containment measures.” — Partha Paul

Many congratulations Partha for your second entry in the top 10!

The Nature India editorial and design teams have chosen ten stunning finalists, that will be rolled out (in no particular order of merit) over the next few days. These entries have been judged for novelty, creativity, quality and print worthiness. Nature India’s final decision to chose the winner will be partly influenced by the engagement and reception these pictures receive here at the Indigenus blog, on Twitter and on Facebook. To give all finalists a fair chance, we will consider the social media engagement each picture gets only during the first seven days of its announcement. The final results will be announced sometime in early February 2021.

Watch this space as we announce the other finalists in the coming days. Like, share and comment on your favourite photos on Twitter and on Facebook with the hashtag #NatureIndphoto to make them win.

The winning pictures will get cash prizes worth $350, $250 and $200 respectively. The top 10 finalists will be featured here, on Nature India’s blog Indigenus and in our subsequent annual issue.

The winner and runners-up will also receive a copy of the Nature India Annual Volume 2020 and a bag of Nature Research goodies. Winning entries stand a chance of being featured on the cover of one of our forthcoming print publications.

Nature India Photo Contest 2020: Finalist #5

Rolling out finalist #5 in the Nature India Photo Contest 2020 themed ‘pandemic’:

Sourav Karmakar, Kolkata, West Bengal

Photo caption: Faithful fielder

“Before the COVID-19 pandemic, this old man walked in a group with other senior citizens at Lodhi Gardens in New Delhi, India. They followed a schedule – evening-walk, physical exercise, badminton and a chat session. In the new normal, most senior citizens are home-bound. This man found a new companion in his dog and tweaked his fitness schedule with the canine sports partner.” — Sourav Karmakar

Congratulations Sourav for getting a spot in the top 10 of the Nature India Photo Contest 2020!

The Nature India editorial and design teams have chosen ten stunning finalists, that will be rolled out (in no particular order of merit) over the next few days. These entries have been judged for novelty, creativity, quality and print worthiness. Nature India’s final decision to chose the winner will be partly influenced by the engagement and reception these pictures receive here at the Indigenus blog, on Twitter and on Facebook. To give all finalists a fair chance, we will consider the social media engagement each picture gets only during the first seven days of its announcement. The final results will be announced sometime in early February 2021.

Watch this space as we announce the other finalists in the coming days. Like, share and comment on your favourite photos on Twitter and on Facebook with the hashtag #NatureIndphoto to make them win.

The winning pictures will get cash prizes worth $350, $250 and $200 respectively. The top 10 finalists will be featured here, on Nature India’s blog Indigenus and in our subsequent annual issue.

The winner and runners-up will also receive a copy of the Nature India Annual Volume 2020 and a bag of Nature Research goodies. Winning entries stand a chance of being featured on the cover of one of our forthcoming print publications.

Nature India Photo Contest 2020: Finalist #4

Unveiling finalist #4 in the Nature India Photo Contest 2020 themed ‘pandemic’:

Kaushik Dutta, Kolkata, West Bengal

Photo caption: Personal protection

“This little boy, struggling to come to terms with life with a mask, seems to believe that his mother might protect him from all calamities, even an unseen virus. The healing and influencing power of mothers in protecting families has been at the forefront of many awareness campaigns and immunisation programmes during public health emergencies such as the COVID-19. Clicked at the Howrah station in West Bengal, India.” — Kaushik Dutta

Congratulations Kaushik for making it to the top 10 in the Nature India Photo Contest 2020!

The Nature India editorial and design teams have chosen ten stunning finalists, that will be rolled out (in no particular order of merit) over the next few days. These entries have been judged for novelty, creativity, quality and print worthiness. Nature India’s final decision to chose the winner will be partly influenced by the engagement and reception these pictures receive here at the Indigenus blog, on Twitter and on Facebook. To give all finalists a fair chance, we will consider the social media engagement each picture gets only during the first seven days of its announcement. The final results will be announced sometime in early February 2021.

Watch this space as we announce the other finalists in the coming days. Like, share and comment on your favourite photos on Twitter and on Facebook with the hashtag #NatureIndphoto to make them win.

The winning pictures will get cash prizes worth $350, $250 and $200 respectively. The top 10 finalists will be featured here, on Nature India’s blog Indigenus and in our subsequent annual issue.

The winner and runners-up will also receive a copy of the Nature India Annual Volume 2020 and a bag of Nature Research goodies. Winning entries stand a chance of being featured on the cover of one of our forthcoming print publications.