A number of phenomena can be observed when an energetic photon interacts with atom and the courses are: absorption, spontaneous emission, stimulated emission, photoelectric effect, Auger effect and pair production [10] , those are depicted in Figure 1.

Except the energetic photons, lower energy photons may strike an atom/particle and come back in different directions what is called scattering. A few scattering processes are: Rayleigh scattering, Rutherford scattering, Raman scattering, Compton scattering

(Compton shift which is given by, where θ is the scattering angle

of the photon, see Figure 2(a)) [11] . In this of colored photon-photon scattering a fixed target of atoms/particles are not considered. Instead of that a moving target of light (light is travelling here) is used from a fixed source (LEDs are static) of light (analogous to the inverse Compton scattering) as depicted in Figure 2(b).

Let me presume that two colored photons respectively are blue and red have approached and scattered with different angles θ and φ from each direction of propagation. The intensity and frequency of incident blue photon are I_b and ν_b respectively; and those of red photon I_r and ν_r. The intensity of the photons is directly proportional to

the number of photons (and more appropriately to the square of the amplitude of the EM waves). According to the optical elastic scattering the energy of the incident photon is conserved and its direction is changed only. It is the case when photon is scattered from an atom, e.g., Rayleigh scattering (Figure 1(f)). On the other hand Raman scattering is an inelastic scattering where scattered photon energy (gained from molecules) is higher than the incident photon (Figure 1(h)). The colored light-light scattering is an inelastic process, and hence incident blue photon transfers some of its energy to the incident red photon at the closest approach. Therefore, scattered red photon gains energy from the system after scattering, both elastic (blue photons) and inelastic (red photons) processes have occurred simultaneously, a new brand of scattering phenomena, may be called “Mondal scattering” on the way, and there is a probability of more than one red photon scattering by a single blue photon. Assuming the scattered intensities and frequencies of blue and red photons are and, and and respectively, the scattering formula has been revealed. In the “Mondal scattering” process energy and momentum of photons must be conserved before and after the collision.

1) According to the energy conservation law,

where h is a Planck’s constant, subscripts b and r indicate the blue and red light, E and I indicate energy and intensity of photons per unit area and per unit time of the respective colors.

2) According to the law of momentum conservation, moment a of the scattered photons have two components: parallel (cosine) and perpendicular (sine). Hence, (i) cosine component is

where c is the speed of light, and (ii) sine component is

Now squaring both sides of Equations (2) and (3) and adding, we have,

Equating Equations (1) and (4) we have,

A few cases can be considered: (i) θ = 0, (then), (ii) θ = π, (then), and (iii) when, Equation (5) reduces to,

Now Equating Equations (1) and (6) we have

When the light incident on the surface of a photodiode (detail of it can be found elsewhere [12] [13] ), it can produce current (i) and voltage (V = iR, where R is the resistance of Multi-meter circuite) which is directly proportional to the incident energy (and energy is proportional to the intensity), i.e.,. Therefore, Equations (6) and (7) can be modified respectively in the following form

And

We can calculate the asymmetry (A) between the scattered blue and red photons from Equations (8) and (9) in the following form,

(In order to avoid much mathematical complication elastic scattering process are taken into account, because determination of scattered frequencies are not possible in the following experimental detection system).

or (11)

Experimentally parameters in the r.h.s. of Equations (10) and (11) are achievable and hence asymmetries are to be obtained.

In order to determine the asymmetry (A) of the colored light a “+” shape experimental apparatus is constructed whose lay-out is illustrated in Figure 3. The length of each arm is 6 cm and diameter is φ = 1.2 cm which are made of steel pipes. Inner surface of the pipe is covered with black paper for the reduction of light-scattering effect. Different colored light emitting diodes (LEDs, detail of it can be found elsewhere [14] ) are used for the source of incident lights and fixed them face to face by using wooden corks at each end of the pipe. The area of a semi-spherical surface of a LED is about 8π mm². Similarly two photodiodes (PDs, model: BPW 34) sensors are used face to face in order to measure the intensity of the scattered light in terms of voltage by connecting with a digital multimeter. The surface area of each PD is about 4 mm².

First the voltages of the incident colored photons in pair are detected individually by each PD. Then PDs are changed from this direct measurement position to the perpendicular positions of each incident colored photon. Then background effect is measured independently of each color on/off conditions and data are subtracted from the data of scattered photons during the analysis. The background arises due to light scattering with air molecules and inner surface of the beam pipe. The experiments are executed in pair of colors with respect to blue only. The results of different colored photons (Row 1 - 4) in pairs are put in order in Table 1. Similarly for the studying of mesh of light-light scattering direct incident light L-1 and L-2 are detected respectively by PD-1 and PD-2 sensors just by removing the sources of color light and coving the mesh light of the room into the beam pipes.

Then PD-1 and PD-2 sensors are perpendicularly set-up and detected scattered photons. The system is oriented 90 degree and repeating the previous steps again. The average data are tabulated in Row-5 and their asymmetries are calculated. Now the whole system is brought outside in a sunlit area and incident and scattered light are detected as well which are also shown in Row-6. Percentage of errors of columns (vi) and (vii) are estimated from the respective data of columns (iv) and (v). The error of scattered asymmetry (row 5, column vii) is bigger than any other calculated values because statistical data (row 5, column v) are inferior to any other rows.