5 :11 A PMT has 10 dynodes. At each dynode one incoming primary electron
creates four secondary electrons. The PMT is used to detect a faint laser
beam that is operating at 632.8 nm. The quantum efficiency of the cathode at
this wavelength is 25 %. The laser power incident on the PMT is 1nW.
(a) Show that the number of incident photons per second at the cathode is
3.19× 109 photons/s. Recall that power is equal to photon energy times
the number of arriving photons per second.
(b) Show that 7.97× 108 photoelectrons are generated at the cathode per
second.
(c) Show that the gain of this PMT is 1048576.
(d) The anode current is the cathode current multiplied by the gain of the
PMT. Show that the anode current is 133.6 μA. Recall that
q = 1.6× 10 −^19 C.
5 :12 Many types of spectroscopic systems require the capability of a measurement
system to view several narrow spectral bands simultaneously. Using
resources from the Web, identify vendors that supply multichannel bandpass
opticalfilters and list some characteristics of some typicalfilters in the visible
spectrum. Consider parameters such as channel spacing, operating spectral
bandwidth, channel isolation, and insertion loss.
References
- S. Donati,Photodetectors: Devices, Circuits, and Applications(Prentice-Hall, New York,
2000) - M. Johnson,Photodetection and Measurement(McGraw-Hill, New York, 2003)
- B.L. Anderson, R.L. Anderson,Fundamentals of Semiconductor Devices(McGraw-Hill, New
York, 2005) - A. Beling, J.C. Campbell, InP-based high-speed photodetectors: tutorial. J. Lightw. Technol.
27 (3), 343–355 (2009) - R. Riesenberg, A. Wutting, Optical detectors, chap. 5, inHandbook of Biophotonics, vol. 1:
Basics and Techniques, eds. by J. Popp, V.V. Tuchin, A. Chiou, S.H. Heinemann (Wiley, New
York, 2011), pp. 297– 343 - C. Jagadish, S. Gunapala, D. Rhiger, eds.,Advances in Infrared Photodetectors, vol.
84 (Academic Press, Cambridge, 2011) - M.J. Deen, P.K. Basu,Silicon Photonics: Fundamentals and Devices(Wiley, Hoboken, NJ,
2012) - G. Keiser,Optical Fiber Communications, chap. 6, 4th US edn., 2011; 5th international edn.,
2015 (McGraw-Hill) - G.C. Holst, T.S. Lomheim, CMOS/CCD Sensors and Camera Systems (SPIE Press,
Bellingham, WA, 2007) - Hamamatsu,Photomultiplier Tube Handbook, 3rd edn. (2007).https://www.hamamatsu.com/
resources/pdf/etd/PMT_handbook_v3aE.pdf - W. Becker,The bh TCSPC Handbook(Becker & Hickl, Berlin, Germany, 2014)
- V. Kochergin,Omnidirectional Optical Filters(Springer, New York, 2003)
5.9 Problems 145