Biophotonics_Concepts_to_Applications
(b) What is the 3-dB electrical bandwidth of this device? Solution: (a) The 3-dB optical bandwidth occurs at the modulation freq ...
4.4.1 Basic Laser Actions A lasing medium can be a gas, a liquid, a solid-state crystal, a semiconductor, or an opticalfiber. De ...
A simple laser design consists of the following: Anactive medium(orgain medium) in which atoms or molecules can be excited to h ...
lasing condition that is dominated by stimulated emission. The lasing efficiency is given by geff¼ dP dI ð 4 : 8 Þ where dP is t ...
diode modules include small size and weight (e.g., 1 mm across and weighing a few grams), low electrical power requirements of t ...
where n is the refractive index of the lasing cavity and L is the cavity length. This can be related to the frequency spacingΔνt ...
The VCSEL is a single-mode laser, which is made mainly for emissions in the 750 – 980-nm range [ 21 ]. A common peak wavelength ...
energized by optically pumping it with a xenonflashtube. Ruby lasers initially were used for tattoo and hair removal, but now us ...
4.4.4 Gas Lasers A wide selection of gas lasers is available for many different types of commercial, hobby, educational, and med ...
Example 4.6In a He–Ne gas laser an electrical discharge pumps helium atoms to a 20.61-eV excited state. This excited helium leve ...
4.6 Summary The biophotonicsfield covers a wide spectrum ranging from about 190 nm in the UV to over 10μm in the infrared. The n ...
4 :4 Excimer lasers generally contain a mixture of a noble gas (such as argon, krypton, or xenon) and a reactive gas (such asflu ...
to an energy level of about 1.430 eV. From this slightly lower excited state a common transition is to an energy level of 0.264 ...
R. Riesenberg, A. Wutting, Optical sources, chap. 4, pp. 263–295, inHandbook of Biophotonics, eds. by J. Popp, V.V. Tuchin, A. ...
Chapter 5 Fundamentals of Optical Detectors Abstract The photodetection devices used in biophotonics disciplines are semiconduct ...
5.1 ThepinPhotodetector. A common semiconductor photodetector is thepin photodiode, shown schemati- cally in Fig.5.1[ 1 – 8 ]. T ...
Example 5.2A high-speed InGaAs pin photodetector is made with a 0.15-μm thick depletion region. What percent of incident photons ...
The high electricfield present in the depletion region causes the carriers to separate and be collected across the reverse-biase ...
kcðlmÞ¼ hc Eg ¼ 1 : 240 EgðeVÞ ð 5 : 4 Þ The cutoff wavelength is about 1.06μm for Si and 1.6μm for Ge. For longer wavelengths t ...
generated electron–hole pairs is very short. The generated carriers thus recombine before they can be collected by the photodete ...
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