Optical Interferometry for Biology and Medicine docx

[...]... increases the optical path length inside the optical cavity There are many possible implementations of the Mach–Zehnder interferometer The drawing in Fig 1.15 is for a free space setup, but the same principle holds for integrated on-chip waveguide interferometers, and for fiber-based interferometers Integrated optical interferometers have much more stable path differences and phase bias than free-space optical. .. Optical Interferometry for Biology and Medicine, Bioanalysis 1, DOI 10.1007/978-1-4614-0890-1_1, # Springer Science+Business Media, LLC 2012 (1.1) 3 4 1 Interferometry Fig 1.1 Representation of a complex number z ¼ x þ iy on the complex plane The x-axis is the real part and the y-axis is the imaginary part The graphical representation of a complex number plots the real part along the x-axis and the... Classes 17 For a detected power of 1 W, a detection bandwidth of 1 Hz, a photon wavelength of 600 m, and a quantum efficiency of 0.7, the NED is an astonishingly small value of Dd ¼ 0.016 fm These parameters are not too far from the anticipated performance of the LIGO gravity wave detector For biosensor applications, on the other hand, detected powers are more typically 10 mW, with detection bandwidths... phenomena and techniques in biological optics This chapter lays the foundation for interferometry applied to biology and medicine It begins with the simplest form of interference between two waves, explains common forms of interferometers, and ends with a short overview of partial coherence and of higher-order interference effects 1.1 Two-Wave Interference The simplest interference involves two independent... systems have noise, and to understand the sensitivity of any optical measurement requires an understanding of that noise A challenge to optical metrology is the many different contributions to noise, for which one or another may dominate, or several may contribute nearly equally Pulling apart which noise mechanisms are participating and dominating an optical measurement is sometimes difficult, because different... Chapter 1 Interferometry All optical phenomena experience interference effects at some level Even light from an incandescent light bulb has partial coherence that can lead to constructive or destructive interference when multiple light paths are combined at a detector The ubiquitous nature of interference underlies many phenomena and techniques in biological optics This chapter lays the foundation for interferometry. .. distinct optical paths are deflected so that they are no longer parallel and hence cross (wavefront-splitting), or whether a single optical path splits to take different paths before crossing or combining (amplitude-splitting) Wavefrontsplitting configurations include Young’s double-slit interference (Fig 1.11) and diffraction generally Amplitude-splitting interferometers include Michelson, Mach–Zehnder and. .. interference contrast is C ¼ 1, 0.8, 0.47, 0.25, 0.12 and 0.062 for b ¼ 1, 4, 16, 64, 256 and 1,024, respectively where the ratio of intensities is b ¼ I1 /I2 When I1 ¼ I2 , there is perfect constructive interference and perfect destructive interference for the appropriate relative phases The graph of the response function is shown in Fig 1.4 for several beam ratios Contrast is an important property... to the real axis and hence is in phase with the reference wave Er Therefore, the phase modulation adds in-phase with the reference and is detected as an intensity modulation 12 1 Interferometry Fig 1.8 Complex representation of phase quadrature The phase modulated field DEs on the signal wave is parallel to the reference wave Er to produce constructive interference 1.1.4 Heterodyne and Beats When there... frequency and phase of the original waves, multiplied by a low-frequency envelope that has the difference frequency, as shown in Fig 1.9 The total intensity varies with time as ITot ¼ 2I ½1 þ CðbÞ cosð2Dot À 2Daފ (1.26) which, on a spectrum analyzer, has frequency side-lobes at the frequency difference Æ jo1 À o2 j 1.1.5 Noise and Detection All optical systems have noise, and to understand the sensitivity . sensitivity for biosensors as well as depth-gating capabilities to opticall y section living tissue. Optical Interferometry for Biology and Medicine presents. Bioanalysis For further volumes: http://www.springer.com/series/8091