Optimal phase modulation for gradient-index optical filters

1993 ◽  
Vol 18 (19) ◽  
pp. 1583 ◽  
Author(s):  
Jeff Druessel ◽  
Peter Haaland ◽  
Jeff Grantham
1994 ◽  
Vol 374 ◽  
Author(s):  
Peter D. Haaland

AbstractGradient index or rugate optical filters are continuous generalizations of the familiar quarterwave stack which find widespread applications in sensor hardening. In the design of a filter or mirror there are infinitely many refractive index profiles n(x) whose wavelength-dependent reflectance R(λ) is specified as a design objective. The relationship between R(λ) and n(x) is nearly that of a Fourier-transform pair. Exploiting this relationship, specifically the physically indeterminate phase of the Fourier transforms, permits constrained optimization of rugate designs. In this contribution we outline the approach of optimal phase modulation and indicate by examples its application to problems in optical limiting.


1989 ◽  
Vol 168 (2) ◽  
pp. 185-192 ◽  
Author(s):  
A.B. Harker ◽  
J.F. Denatale

Author(s):  
Z.M. Wang ◽  
J.P. Zhang

High resolution electron microscopy reveals that antiphase domain boundaries in β-Ni3Nb have a hexagonal unit cell with lattice parameters ah=aβ and ch=bβ, where aβ and bβ are of the orthogonal β matrix. (See Figure 1.) Some of these boundaries can creep “upstairs” leaving an incoherent area, as shown in region P. When the stepped boundaries meet each other, they do not lose their own character. Our consideration in this work is to estimate the influnce of the natural misfit δ{(ab-aβ)/aβ≠0}. Defining the displacement field at the boundary as a phase modulation Φ(x), following the Frenkel-Kontorova model [2], we consider the boundary area to be made up of a two unit chain, the upper portion of which can move and the lower portion of the β matrix type, assumed to be fixed. (See the schematic pattern in Figure 2(a)).


2014 ◽  
Vol E97.B (10) ◽  
pp. 2102-2109
Author(s):  
Tsubasa TASHIRO ◽  
Kentaro NISHIMORI ◽  
Tsutomu MITSUI ◽  
Nobuyasu TAKEMURA

Author(s):  
Yin S Ng ◽  
William Lo ◽  
Kenneth Wilsher

Abstract We present an overview of Ruby, the latest generation of backside optical laser voltage probing (LVP) tools [1, 2]. Carrying over from the previous generation of IDS2700 systems, Ruby is capable of measuring waveforms up to 15GHz at low core voltages 0.500V and below. Several new optical capabilities are incorporated; these include a solid immersion lens (SIL) for improved imaging resolution [3] and a polarization difference probing (PDP) optical platform [4] for phase modulation detection. New developments involve Jitter Mitigation, a scheme that allows measurements of jittery signals from circuits that are internally driven by the IC’s onboard Phase Locked Loop (PLL). Additional timing features include a Hardware Phase-Locked Loop (HWPLL) scheme for improved locking of the LVP’s Mode-Locked Laser (MLL) to the tester clock as well as a clockless scheme to improve the LVP’s usefulness and user friendliness. This paper presents these new capabilities and compares these with those of the previous generation of LVP systems [5, 6].


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