Single Photon InterferenceFreshman Quantum Optics Quiz

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Name

  1. The observation of a single photon is at the core of this lab. Which formula may be used to determine the number of photons per second produced by a laser? (P is the laser power, λ is the wavelength of the light, h is Planck’s Constant, and c is the speed of light.)
  2. N = (hc)/(Pλ)
  3. N = (P2λ)/(hc)
  4. N = (hc)/(P2λ)
  5. N = (Pλ)/(hc)
  6. How many photons/s with a wavelength of 633 nm are produced at a laser power of 1 mW (Recall that h = 6.63 x 1034 Js)?
  7. 3.18 x 1015
  8. 3.18 x 1013
  9. 3.18 x 1012
  10. 3.18 x 109
  11. What formula may be used to determine the number of photons/meter?
  12. N = (h)/(Pλ)
  13. N = (Pλ)/(hc)
  14. N = (Pλ)/(h)
  15. N = (Pλ)/(hc2)
  16. Which filter transmission valueshould be selected to attenuate a 1 mW, 633 nm laser beam to a single-photon level(assume ~100-m distance between photons)?
  17. 10-7
  18. 10-5
  19. 10-9
  20. 10-11

  1. Will you expect to obtain antibunching (separation of all photons in the source) from the attenuated laser beam?
  2. Yes, under the conditions specified in question #4.
  3. Yes, under any conditions.
  4. No, not under the conditions specified in question #4, only.
  5. No, attenuated laser beams have classical photon statistics.
  6. How did your experiment demonstrate the wave-particle duality of photons?
  7. Photons as particles hit the entire detector area.
  8. Photons as particles hit the detector only in specific places (where the interference pattern occurs).
  9. Photons produce only interference fringes (they cannot be distinguished as separate particles).

Questions #7 and 8. Given schematics i and ii, and equations iii and iv as shown below.

i. ii.

iii. (z λ)/d, where d = the single slit width, iv. (z λ)/d, where d = the distance

between the two slits

z is the distance between the screen with the slits and the observer’s screen, λ is a wavelength of light

  1. A student observes the pattern shown at the right. Which schematic (i or ii) and which equation (iii or iv) will produce the pattern that is observed?
  1. i and iiib. i and iv c. ii and iiid. ii and iv
  1. A student observes the pattern shown at the right. Which schematic (i or ii) and which equation (iii or iv) will produce the pattern that is observed?
  1. i and iiib. i and iv c. ii and iiid. ii and iv
  1. If, instead of the laser beam used in questions 7 and 8, we used a gun firing bullets. Which pattern will you observe, A or B?

A. B.

  1. Which schematic represents a Mach-Zehnder interferometer?

  1. How will you align the interferometer?
  2. It is important to overlap two spots from two arms of the interferometer, at its output only
  3. It is important to overlap two spots from two arms of the interferometer, only at a distance far away
  4. It is important to overlap two spots from two arms of the interferometer, at the output and at a distance far away
  5. Explain what is a “which-way information”. Explain it on the example of your experiments.
  6. If photon knows path (the polarization in each arm is defined), interference fringes will appear on the screen.
  7. If photon does not know path (the polarizer at the output of the interferometer was set for 45o), interference fringes will appear on the screen.
  8. If photon does not know path (the polarizer at the output of the interferometer was set for 45o), no interference fringes will appear on the screen.
  9. If light is nothing but a stream of particles (called photons), why doesn’t a stream of bullets give rise to an interference pattern similar to that of photons? (Please provide your answer in the space provided below.)
  1. Write the equation for the De Broglie wavelength forthermal electrons. (Where h = Planck’s Constant, p = momentum of the electron, c = velocity of light, and m = electron mass.)
  2. λ = h/mc2
  3. λ = h/mv
  4. λ = h/mc