Optical phase

The preparation of the reflecting silver layers for MBI deserves special attention, since it affects the optical properties of the mirrors. Another important issue is the optical phase change [ ] at the mica/silver interface, which is responsible for a wavelength-dependent shift of all FECOs. The phase change is a fimction of silver layer thickness, T, especially for T < 40 mn [54]. The roughness of the silver layers can also have an effect on the resolution of the distance measurement [59, 60]. 

Before concluding this sketch of optical phases and passing on to our next topic, the status of the phase in the representation of observables as quantum mechanical operators, we wish to call attention to the theoretical demonstration, provided in [129], that any (discrete, finite dimensional) operator can be constructed through use of optical devices only. 

Usually we are only interested in mutual intensity suitably normalised to account for the magnitude of the helds, which is called the complex degree of coherence 712 (r). This quantity is complex valued with a magnitude between 0 and 1, and describes the degree of likeness of two e. m. waves at positions ri and C2 in space separated by a time difference r. A value of 0 represents complete decorrelation ( incoherence ) and a value of 1 represents complete eorrelation ( perfect coherence ) while the complex argument represents a difference in optical phase of the helds. Special cases are the complex degree of self coherence 7n(r) where a held is compared with itself at the same position but different times, and the complex coherence factor pi2 = 712(0) which refers to the case where a held is correlated at two posihons at the same time. 

The detector must be able to measure optical phases of about 10 rad. 

The spatially periodic temperature distribution produces the corresponding relxactive index distribution, which acts as an optical phase grating for the low-power probing laser beam of the nonabsorbed wavelength in the sample. The thermal diffusivity is determined by detecting the temporal decay of the first-order diffracted probing beam [°o exp(-2t/x)] expressed by... 

Koliopoulos, C.L. Interferometric Optical Phase Measurement Techniques, Ph.D. Thesis, 1983, The University of Arizona, University Microfilms International, Ann Arbor, Michigan. 

Heideman R.G., Lambeck P.V., Remote opto-chemical sensing with extreme sensitivity design, fabrication and performance of a pigtailed integrated optical phase-modulated Mach-Zehnder interferometer system, Sens, and Actuat. B 1999 61 1 GO-127. 

Operator definitions, phase properties, 206-207 Optical phases, properties, 206-207 Orbital overlap mechanism, phase-change rule, chemical reactions, 450-453 Orthogonal transformation matrix ... 

Fig. 9.14 (a) The measured variation of the Mach Zehnder interferometer (MZI) output intensity as a monolayer of streptavidin is bound to the surface, and (b) the optical phase change calculated from this intensity data... 

The measured intensity modulation can then be used to recover the original optical phase change Aphase shift, shown in Fig. 9.14b, is directly proportional to the density of molecules on the surface, as long as the film thickness is much less than the evanescent field penetration depth of <5 162 nm. 

The sample used for a demonstration of broadband TPF imaging with compressed PCF supercontinuum in Figure 7.17 was a commercially available test slide (Invitrogen FluoCells , prepard slide 1, containing labeled bovine pulmonary artery endothelial cells). The conventional optical phase-contrast microscopy image... 

Switching electronic population to different final states with high efficiency via SPODS is a fundamental resonant strong-field effect as the only requirement is the use of intense ultrashort laser pulses exhibiting temporally varying optical phases, such as phase jumps [67, 68, 70, 71] or chirps [44, 72]. Only recently, these concepts were transferred to molecules, where the coupled electron-nuclear dynamics have to be considered in addition [73,74]. 

In Section 6.5.3, we report on experiments exploring the limits of the electronic response to changes of the optical phase. In these experiments, a switching precision in the order of sub-10 as was demonstrated [8],... 

Figure 6.10 Ultrafast efficient switching in the five-state system via SPODS based on multipulse sequences from sinusoidal phase modulation (PL). The shaped laser pulse shown in (a) results from complete forward design of the control field. Frame (b) shows die induced bare state population dynamics. After preparation of the resonant subsystem in a state of maximum electronic coherence by the pre-pulse, the optical phase jump of = —7r/2 shifts die main pulse in-phase with the induced charge oscillation. Therefore, the interaction energy is minimized, resulting in the selective population of the lower dressed state /), as seen in the dressed state population dynamics in (d) around t = —50 fs. Due to the efficient energy splitting of the dressed states, induced in the resonant subsystem by the main pulse, the lower dressed state is shifted into resonance widi die lower target state 3) (see frame (c) around t = 0). As a result, 100% of the population is transferred nonadiabatically to this particular target state, which is selectively populated by the end of the pulse.

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