Past Webinars (In reverse chronological order)

6th Webinar  (24th September, 2023  18:00 – 19:30 IST)

Introduction to Metamaterials” by Achanta Venu Gopal, Director, CSIR – National Physical Laboratory (See poster Here)

Metamaterials are designed materials with sub-wavelength features arranged in either periodic or aperiodic patterns. Though the field started with the invention of negative index materials, it evolved to encompass a wider range of materials. Two broad classifications are, metal-dielectric and all-dielectric metamaterials. Metal-dielectric metamaterials support plasmons that localize light to sub-wavelength dimensions and this beat diffraction limit. The plasmon mediated local field as well as resonances originating from the structure lead to exotic properties for this class of metamaterials. All-dielectric metamaterials on the other hand offer advantages like low or no loss and can have unique properties. In this talk, negative index, plasmonic, and all-dielectric metamaterials will be introduced and examples of metamaterial structures will be discussed.

This Webinar recording is available in the link:

5th Webinar  (10th September, 2023  18:00 – 19:30 IST)

Early History of Radio Research in India” by Animesh Maitra, Professor, Institute of Radiophysics and Electronics, University of Calcutta, Kolkata (See poster Here)

Radio research in India began nearly simultaneously with the advent of wireless telegraphy in Europe during the 1890s. Sir J. C. Bose took a groundbreaking step by generating microwave signals in his laboratory at Presidency College, Calcutta in 1894. His pioneering work not only demonstrated the quasi-optical properties of electromagnetic waves but also led to the development of various components crucial for radio communication systems.
Later, Professor S. K. Mitra, at the University of Calcutta, embarked on experimental investigations into the ionospheric propagation of radio waves shortly after the discovery of the ionosphere by Appleton and Barnett in 1924 that had significant implications on radio probing of the atmosphere. Efforts of these two pioneers resulted in many significant inventions and advancements that laid the foundation of radio and space research in India.
This talk will highlight the accomplishments of these two pioneers and the impact their work had on the courses of radio research in India.

This Webinar recording is available in the following link:

4th Webinar  (13st August, 2023  18:00 – 19:30 IST)

Lunar Missions of India” by A S Kiran Kumar (Padma Shri), Vikram Sarabhai Professor, ISRO & Member of Space Commission, Govt of India (Formerly, Chairman, ISRO (See poster Here)

Moon the closest celestial companion of the Earth has always fascinated and enthralled humans from time immemorial. As the technological capability of India grew since its Independence in 1947, it has developed probes which have been sent to the Moon and the Mars.

This talk brings some details of India’s efforts to reach and  explore the Moon  through space probes Chandrayaan One (2008), Two (2019)  and Three (2023).

This Webinar recording is available in the following link:

3rd Webinar  (1st August, 2023  18:00 – 19:30 IST)

Ultra-low frequency gravitational wave search using radio astronomy” by Bhal Chandra Joshi, Raja Ramanna Chair (Emeritus Professor), National Centre for Radio Astrophysics (NCRA), Pune (See poster Here)

Gravitational waves (GWs) are an essential outcome of Einstein’s General theory of relativity, but eluded detection for about a century. High frequency GWs were announced in 2015, while the low frequency GWs window appears to be opening in a recent announcement last month by experiments world-wide including Indian Pulsar Timing Array experiment (InPTA), which uses a radio astronomy means employing the premier Indian radio astronomy facility, the upgraded Giant Meterwave Radio Telescope (uGMRT).

In this talk, linkage of radio science with a totally different messenger that GWs are will be examined after a brief introduction to GWs and recent announcement. After highlighting the need for precision, the required radio instrumentation in the form of antennas, receivers and clocks will be discussed in the context of the uGMRT. The talk will conclude with a description of the InPTA experiment and its results in the context of three other international experiments, namely the European Pulsar Timing Array (EPTA), the North American Gravitational Wave Observatory (NANOGrav) and the Parkes Pulsar Timing Array (PPTA), outlining the road ahead with the currently in progress data combination of all these experiments under the auspices of the International Pulsar Timing Array (IPTA).

This Webinar recording is available in the following link:

2nd Webinar  (25th July, 2023  18:00 – 19:30 IST)

Probing the Universe using radio waves with the GMRT” by Yashwant Gupta, Distinguished Professor & Centre Director, National Centre for Radio Astrophysics (NCRA), Pune (See poster Here)

The demonstration of how to transmit and receive radio waves, first done by Sir J.C. Bose in 1894, led to the opening up of a new window to the Universe. India has a strong tradition in this branch of astronomy, starting with Prof Govind Swarup who kicked off activities in this area at TIFR in 1963.

In this talk, we will trace the fascinating story of radio astronomy and the engineering behind it, with special emphasis on its growth and current status in India, ending with the frontline Indian facility — the Giant Metrewave Radio Telescope (GMRT). The GMRT, a world class low frequency radio observatory has been operational since 2002. We have recently completed a major upgrade of the GMRT employing some cutting edge new technologies. This will keep the GMRT at the forefront as one of the most sensitive facilities in the world in the 100 to 1500 MHz range for the next decade or so.

This talk will spotlight some of these multi-disciplinary technological aspects of the GMRT, and also take a look into how it has improved our understanding of the Universe, and what the future holds. In particular, we will look closely at how the GMRT is used to carry out interesting and precise observations of pulsars – rapidly spinning neutron stars.

The Webinar recording is available in the following link:

1st Webinar  (20th July, 2023  18:00 – 19:30 IST)

Solar Magnetic Fields and Explosive Solar Events: Can they Impact Our Technologically Dependent Life?” by Janardhan Padmanabhan, INSA senior Scientist, Physical Research Laboratory, Ahmedabad, India (See poster Here)

Mankind’s future in the 21st century is coupled inextricably to satellite systems which modulate all facets of human life from trade and commerce to transport, navigation, communication, science, education, medicine, warfare, and global peace. The strong link between solar activity [flares, coronal mass ejections (CMEs), changing solar magnetic fields] and conditions in near-earth space, and the terrestrial magnetosphere, which can adversely affect communication, terrestrial power grids or even destroy satellite systems, is therefore vitally important. Understanding and eventually being able to predict these events is crucial as it would enable protecting our satellite systems, our very future as a modern race, and also in understanding the ionosphere, radio communication and non-anthropogenic climate effects associated with global cooling, and unusual weather patterns. A deep understanding of the physics driving solar explosive events, using the best available technology is the key to mitigating this clear and present danger to our way of life.

In this talk I will present our observations using around four decades of solar magnetic field data, radio observations of solar wind micro-turbulence levels, and our data driven modelling of the Terrestrial Magnetosphere that together gives us valuable insights into many of these issues.

This Webinar recording is available in the following link: