Quality control systems have been developed to remotely measure the diameter of wires using diffraction. A wire with a stated diameter of 170 μm blocks the beam of a 633 nm laser, producing a diffraction pattern on a screen 50.0 cm distant. The width of the central maximum is measured to be 3.77 mm. The wire should have a diameter within 1% of the stated value.Does this wire pass the test?

4. (a) A laser that emits a diffraction-limited beam (Xo = 632.84 nm), produces a light spot on the surface of the Moon a distance of 376000 km away. How big is the circular aperture of the laser, if the light spot has a radius of 58 km? Neglect any effects of the Earth's atmosphere. (b) Consider a ruby crystal with two energy levels separated by an energy difference corresponding to a free-space wavelength Xo = 694.3 nm, with a Lorentzian lines hape of width Av=330 GHz. The spontaneous lifetime it tsp = 3 ms and the refractive index of ruby is n = 1.76. What value should the population difference N₂ - №₁ assume to achieve a gain coefficient () = 0.5 cm-¹ at the central frequency? (c) How long should the crystal be to provide an overall gain of 10 at the central frequency when y() = 0.5 cm-¹?

Quartz is a uniaxial birefringent material with refractive indices no=1.5534 and ne=1.5443. It is desired to make a quarter-wave plate of quartz for use with a Sodium laser of wavelength λ0=589 nm. Calculate the minimum thickness of the plate.Give your answer in micrometers to 1 d.p.

In ATR-FTIR, the refractive index of the crystal used must be significantly lesser than that of the sample.  True  False

X-rays of wavelength 0.0628 nm are scattered from a crystal with a grazing angle of 11.3°. Assume m = 1 for this process. Calculate the spacing between the crystal planes. d = nm

Non-conducting materials can be studied by scanning tunneling microscope(STM). 0 True 0 False

9. Consider TE oblique incidence with 30 degree incidence angle from the air (n=1) to the semiconduc tor (n=3.5). The optical wavelength is 1.5 µm. We want to coat a thin film on the semiconductor to achieve zero reflection for this particular case. The coating material is with the refractive index n and the thickness d. (1) What is the power reflectivity of the interface without the coating. (2) Please determine the required d and n to achieve zero reflectivity.