australian universities.aryabhata had also introduced the concept of infinitesimals; his...

Mr. Peter Ford, Session Chairman Our next speaker is Prof. Ajoy Ghatak. He received the 2008 SPIE Educator award and the 2003 Optical Society of America Esther Hoffman Beller award. He is a Fellow of OSA & SPIE. He has authored several books and received a DSc (Honoris Causa) from University of Burdwan in 2007. He has been a visiting professor at several European, US and Australian universities. Prof. Ajoy Ghatak

Good morning! I am going to take you back to the evolution of the science and education in general in our country and give you a historical perspective of this. Probably near the end I will tell you why we are what we are. First I will talk about the heritage. Because for many of you this is probably the first visit to India, so I thought to tell you what has been our past.

Science and Education in India – Ajoy Ghatak page 55

Nowadays some of these remains are located in India and some of them are in Pakistan. We had tremendous city planning that was in existence about 3000 years back. Even arithmetic operations, which are written in Sanskrit as Ganit, such as addition, subtraction, multiplication, fractions, squares, cubes and roots are enumerated in a manuscript by Ved Vyas (pre-1000 BC). The concept of zero also appears to have originated in ancient India. Examples of geometric knowledge, which is known in Sanskrit as Rekha-ganit are to be found in the Shulba-Sutras (about 800 BC). The Shulba-Sutras are considered to be appendices to the Vedas.


Around 7th century BC, the Astronomer Yajnavalkya showed that the distance of the Moon and the Sun from the Earth is 108 times the diameters of these heavenly bodies, which were close to the modern values of 110.6 for the Moon and 107.6 for the Sun. It is an amazing fact, that the angular diameter of the sun and the moon as seen from the earth is almost the same.

S C Kak, “Birth and Early Development of Indian Astronomy” in H.

Selin, Astronomy Across Cultures: The History of Non-Western

Astronomy, Kluwer, Boston. (2000).


Aryabhata (476–550 AD) was the first in the line of great mathematician-astronomers.

In 499, Aryabhata propounded:•planets rotate on their axescausing day & night and followelliptical orbits around the Sun•He also explained the causesof the solar and lunar eclipsesand predicted their times.

Statue of Aryabhata on the grounds of Inter-University Centre for Astronomy and Astrophysics (IUCAA) in Pune


Aryabhata had also introduced the concept of infinitesimals; his differential equations were elaborated by Bhaskaracharya (12th century) who derived the differential of the sine function. In any western text the differential calculus is usually attributed to Newton and Leibnitz. But actually the concept of differential calculus was elaborated by Bhaskaracharya in India.

Bhaskaracharya (1114 -1183) was a teacher, a mathematician and also an astronomer.


The Jagannath Temple in

Puri was built in the 11th century; by then, construction engineers were using iron girders and beams on a scale unknown in any other part of the world.

The most significant use of iron beams was in the temples of Puri and Konarak in the eastern part of India, the location of which can be seen on the following map together with this great marvel of architecture, which involves a tremendous amount of civil engineering, the Taj Mahal.


Taj Mahal in Agra built during 1632–1653


The Mughal Empire (1526 – early 18th century)

During the Moghul period, mathematical and scientific texts from India were increasingly being translated into Arabic and Persian. These translated texts were also available in Europe. To quote from the book

Science in Translation

by Beverly Adab,

Aston University, Birmingham, UK

…. Texts from Persia and India also contributed to Islamic astronomy,

bringing together elements of Greek science, …..


The university was an architectural and environmental masterpiece. It had dormitories for students, perhaps a first for an educational institution, housing 10,000 students in the university’s heyday and providing

accommodations for 2,000 professors. Nalanda was also the most global university of its time, attracting pupils and scholars from Korea, Japan, China, Tibet, Indonesia, Persia and Turkey. The university died a slow death about the time that some of the great European universities, including those in Oxford and others in Europe, were just getting started, and more than half a millennium before Harvard or Yale were established. Its demise was a result of waning enthusiasm for Buddhism in India, declining financial support from successive Indian monarchs and corruption among university officials. The final straw was the burning of the buildings by Muslim invaders from what is now Afghanistan. Then came the relatively dark period in the development of mathematics and science in India: Schools of learning were converted to madarsahs. The Hindu Gurukuls also succumbed to the influence of orthodox Vedantism. The religious fanatism, that entered our country around 1100 almost stopped the development of mathematics and science.


The Renaissance By the middle of the 15th century, the wealth of Europe allowed the resurgence of interest in science, which did not happen in India but was seen as an aid to trade and commerce. Indeed, the scientific revolution, beginning around the year 1600, is a convenient boundary between ancient thoughts and classical physics.


This was the beginning of the Industrial Revolution in Europe, but it did not take place in India. Indeed, in the beginning of the 19th century there were only few schools and colleges – these were mainly around Bombay, Calcutta and Madras where there were British residents in large numbers.


In 1857, three universities were set up inBombay, Calcutta and Madras,

similar to the structure of the University of London.

This was the starting point of higher education in India.


That was a turning point in the development of science and technology in India.


In the year 1893, Swami Vivekananda and Jamshetji Tata were on board a ship going to Canada. Swamiji asked Tata where he was going and what was the mission. Tata said, “Swamiji, I am going with a mission to bring steel industry to our country”.

To which Swamiji said, “It is indeed a beautiful mission. However,

I would like to suggest that whatever amount you spend to get the process of making steel, simultaneously you should learn the metallurgical science of making steel also. I would prefer you to start an institute, a laboratory to do advanced research on the subject.”


I have tried to highlight 3 things:

1. We have a very rich heritage.

2. We should be extremely careful of religious fanaticism – that can put us to negative growth.

3. By vigorous pursuit of original research and giving freedom to the academic institutions, the country will prosper and the backwardness of the country can be removed. I am working in the general area of fiber optics and I would like to give you some information on this topic in the next slides.


Light is being guided through this optical fiber by the phenomenon of total internal reflection. On the next slide I show light propagating through an optical fiber whose core has been doped with erbium. Population inversion in the erbium doped fiber is created by means of a pump at 980 nm wavelength. When the population inversion is created, incoming light pulses at 1550 nm wavelength get amplified. One can have a gain of about 30 dB over an entire wavelength region; a 30 dB gain corresponds to power amplification by a factor of 1000.


1530 1540 1550 1560 1570

Typical Gain Flattened EDFA

Ga

in (d

B)

(nm)


The EDFA was invented in 1987 by a group

led by David Payne from the University of

Southampton and a group led by Desurvire

from AT&T Bell Laboratories the EDFA

brought about a revolution in fiber optic

communication systems.

David Payne

Desurvire behind submarine-cable repeaters


These optical amplifiers are now made in India and are used in optical communications in our country. The advent of the erbium-doped fiber amplifier has resulted in a tremendous increase in the information that can be carried through an optical communication link. Before 1990 there could be only one wavelength that could be passed through an optical fiber. But by the early 90‘s the EDFA was commercially available, thereby one could

simultaneously transmit hundreds of wavelengths through one optical fiber, resulting in increase of the capacity of the optical network and a decrease in the cost of the system. In 2001 Alcatel and many other companies propagated simultaneously 256 individual wavelength channels through one optical fiber, sending 10.2 TB/sec information. This implies 2.5 billion telephone channels through one hair thin optical fiber. There has been a revolution, that has taken place. In India, also, there has been a considerable growth in the installation of fiber optic communication systems. Because of this, the cost of the information processing has come done significantly.


Optical fibers are installed around the world as well as in India, as can be seen on the next slides.


Slide courtesy Dr. Atul Srivastava


A very beautiful experiment in fiber optics is seen here. When you send very short duration infrared light pulses through special optical fibers (characterized by very small mode field diameters) then because of non-linear effects, the entire white light spectrum can get created, i.e. you start off with one wavelength of light and you end up with the entire wavelength range of the visible light spectrum.


There is another application of the optical fiber, in which you have light being amplified and resonating between two mirrors, resulting in the formation of fiber lasers. There is a lot of work going on in India producing fiber lasers. So the future is expected to be full of light! Thank you so much.


australian universities.aryabhata had also introduced the concept of infinitesimals; his...

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