Optics Answers

In color center laser, what are the active medium, host material, and laser wavelength? Illustrate the factor, on which laser wavelength depends?

How to lower down the laser threshold in Nd-glass laser and what we want to achieve (purpose/get) by lowering down it?  

Where ND is neodymium.

For an optical resonator, what is the physical significance of the equation, n(ν)dν = 8π(ν³/c³) dν? 

where ν stands for frequency, c for velocity of light, and Nd for neodymium.   

Draw the level scheme (schematic) of the He-Ne laser system. Demonstrate it, why we use He in He-Ne laser system?

Where L stand for laser, He stand for Helium and Ne stand for Neon.

If the mirror separation d = 50 cm changes by 2 nm, what would be the change in relative frequency? If the laser frequency is νL = 4 x 1014s-1, what would be the value of ∆νL=?

Beamwidth (between first nulls) will be for an antenna at 3 MHz with directivity of 100

An optical fibre is made of glass with a refractive index of 1.55 and is clad

with another glass with a refractive index of 1.51. The fibre has a core

diameter of 50µm and is used at a light wavelength of 0.8 µm.

(a) What NA does the fibre have?

(b) What is the acceptance angle?

One-dimensional crystal assembled from three identical atoms connected to one another and to the walls by identical springs. Find the normal modes of the given system. Plot the relative displacements versus time for all three normal modes.(consider the connection as wall-spring-atom1-spring-atom2-spring-atom3-spring-wall).

Consider a cavity consisting of two plane mirrors separated by a distance 60 cm in air. 

Calculate the mode number corresponding to the wavelength λ=600 nm. Also 

calculate the frequency spacing between the two longitudinal modes.

Consider a wavelength multiplexer made from

circulators and fiber Bragg gratings. Assume the

input optical power of each wavelength is through

24 is 1 mW. Let both the insertion loss and the

throughput loss of each FBG be 0.25 dB, and let the

insertion loss of a circulator be 0.6 dB. What is the

power level of each wavelength in through h4

emerging from the final circulator ?