The Visible Light

Washing soap and glycerin were among the six ingredients which were mixed to form a transparent crystal placed on the table especially designed in the longest corridor of the school. The team of scientists had assembled to observe the path-breaking experiment scheduled to be conducted on teachers' day held recently. The corridor was fully covered with black thick curtains. The specially designed table was optically levelled with the help of Ruby Laser. The same Laser pointer was also used to straighten the translucent jelly wire not thicker than the little finger but covering the entire length of the long table covering the almost entire length of the corridor. A sturdy tripod stand was also fixed at one end of the table at the top of which there was a platform where laser pointers were fixed which were used to level the table and also helped the jelly wire to lay straight. 

Scientists from the Indian Institute of Delhi, Raja Ramanna Centre for Advanced Technology, Indian Space Research Organisation and Dibrugarh University were assembled there in the conference hall among the other well-known scientists in the field of experimental physics, space technology and telecommunications. The Principal had introduced the young scientist Mohan, a student of class IX of his institution who had to demonstrate the invention which he had made. There appeared Mohan and the august gathering suspiciously saw a boy who had just entered in his teens appearing in school uniform holding a pointer and smiling. The principal noticed the reactions on their faces which could not reduce the confidence which he had in the calibre of the prodigy- Mohan.

The spark for this experiment had ignited in the mind of Mohan when he was attending the science class. The teacher was teaching the chapter light. The basic nature of light was being discussed in the class. The teacher explained that light travels in a straight line. The speed of light is the maximum attainable speed by any particle having mass. Light is invisible but makes things visible. 

"Sir, why can we not see light?", suddenly the voice of Mohan was heard in the otherwise pin-drop silent class. Mr Upadhyay, who was busy explaining the chapter and was writing something on the board, turned around and saw Mohan standing and asking the question. He tried to explain by saying- Light is a form of energy. We can not see energy. It falls on any object and gets reflected. The reflected light enters into our eyes and the image is formed on the part of the eyes called the Retina. The image is sent to the brain through the optic nerves and we see the object.'' 

Mohan kept on thinking. It was hard for him to believe that 'Light' is invisible. 'Can we make light visible?' was the question hovering in his mind. He lied down on his bed after coming from school. It was a hot day. He switched on the ceiling fan. As the fan gained in speed, the blades became invisible. He sprang into action and started playing on the regulator of the fan, eyes on the ceiling and mind busy registering the minute details. He called the teacher.

''Hello, Upadhyay here''

''Sir, Good Afternoon, this is Mohan. Sir, what if the speed of light can be controlled? Can we make it visible?''

''How? Not understood. Please come again..''

''Sir, the way we can control the speed of a fan by a regulator, can we not control the speed of light by devising any such regulator.''

''In principle, it may be done. Think about it. Let us discuss it tomorrow in the school.''

''Ok, Sir. Thank you, Sir! 

But he could not wait. After half an hour he was in his residence, and the discussion extended for three hours that day. It was the beginning of the countless discussion, experiments, and engagements held during the last three months. The result was to be shown to the observers deputed by the Indian Science Organisation.

During the last three months, they had visited labs of RRCAT, Allahabad, Kolkata, and IIT Delhi and had developed an 'Electromagnetic Regulator' which could reduce the speed of light rays. The speed of light was reduced considerably if passed through the electromagnetic tunnel they had devised. The emitted light was allowed to pass through the newly developed crystal to reduce the speed further. The nature of light was to be observed in the experiment to be demonstrated today.

The scientists were fully attentive from the first slide of the presentation in which Mohan introduced the experiment and the principles of physics involved in the process. He explained that light is considered an electromagnetic wave. The light when passed through the specially designed electromagnetic tunnel reduces the speed. He went on to explain that light does not require any material medium for its movement. It slows down in optically denser media. The team of the school has developed a crystal that reduces the speed of light by one-hundredth times per meter of its length. The combination of the two - 'the electromagnetic tunnelling method' and the other 'using specially developed crystal’, in the present setup, has the capability to bring down the speed of light by just one meter in one sec. This speed can further be reduced by increasing the length of the crystal.

He explained each and every step involved in the experiment. He had to answer so many queries raised by the learned audience. A few of the tricky answers were given by his teacher Mr Upadhyay. All the scientists were theoretically satisfied by the way he had explained but some among them were still not sure of the final result.

After the tea break, all assembled there in the corridor that was converted into a dark-room lab. They inspected each element of the experimental set-up with curiosity and asked Mohan to start the demonstration. The light was allowed to pass through the Electromagnetic tunnel and then the long crystal, placed on the specially designed table. The CCD and the monitor which were placed to detect light were showing the desired output. But, the speed of light emitting from the other end of the crystal was still higher than the desired level.

 ''Sir, either we have to increase the length of the crystal or we have to increase the number of turns in the electromagnetic coil." Said Mohan to the Principal who was accompanying Mohan. Mr Upadhyay was also there. 

Mr Upadhyay said, ''Increasing the turns will become riskier as it will require an additional cooling system which we can not afford now.  The continuous action of the electromagnetic tunnel was very risky as it would produce excessive heat that may cause a fire."

A quick decision was to be taken. They decided to lay another meter of crystal on an extended table. It took another forty minutes to set up the same. The experiment was again started. The CCD placed at the end of the crystal strip showed the remarkable behaviour of the light incident on it. Another CCD placed at right angles to the propagation started showing glow at regular intervals. It was an indication that the light packets, photons, are being detected at even right angles of the light motion. Observing this, the scientist remarked "Unbelievable!" and asked others to observe from his location. 

The experiment was to be paused for a few min due to excess generation of heat. It resumed after half an hour. All scientists observed slow-moving photons moving at equal intervals. These photons are visible now due to their slow motion. They all started clapping and congratulated Mohan, who burst into tears. He had made light visible.

This experiment led to the development of different experimentations in the field of communication, computing and the other scientific fields. Mohan is now working with the scientists for further development in his experiments.