Refractive index change in photochromic diarylethene derivatives and its application to optical switching devices

1997 ◽  
Vol 105 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Mitsutoshi Hoshino ◽  
Fumihiro Ebisawa ◽  
Takashi Yoshida ◽  
Ken Sukegawa
Keyword(s):  
Refractive Index ◽  
Optical Switching ◽  
Refractive Index Change ◽  
Index Change ◽  
Optical Switching Devices ◽  
Switching Devices

DFB Waveguide All-Optical Switching Devices Employing Pump-Induced Refractive Index Change in GaInAsP

2007 ◽  
Vol 31 ◽  
pp. 206-208 ◽  
Author(s):  
Tetsuya Mizumoto ◽  
Yoichi Akano ◽  
Kazuhiko Tamura ◽  
Masaki Yoshimura
Keyword(s):  
Refractive Index ◽  
Optical Switching ◽  
Refractive Index Change ◽  
Distributed Feedback ◽  
Temporal Response ◽  
Index Change ◽  
All Optical ◽  
Optical Switching Devices ◽  
All Optical Switching ◽  
Switching Devices

A pump-induced refractive index change was measured in a passive GaInAsP waveguide together with its temporal response. Also, the temporal response of distributed feedback (DFB) waveguide transmittance modulated by the pump-induced index change was experimentally investigated for an application to all-optical switching devices.

TYPE-II SUPERLATTICES AND VARIABLE OVERLAP SUPERLATTICES IN TOTAL INTERNAL REFLECTION SWITCHES FOR THE LONGWAVE INFRARED

1993 ◽  
Vol 02 (03) ◽  
pp. 415-436 ◽  
Author(s):  
E.R. YOUNGDALE ◽  
J.R. MEYER ◽  
C.A. HOFFMAN ◽  
F.J. BARTOLI ◽  
W.I. WANG
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Total Internal Reflection ◽  
Optical Switching ◽  
Refractive Index Change ◽  
Realistic Model ◽  
Internal Reflection ◽  
Type Ii ◽  
Index Change ◽  
Type Ii Superlattices

We derive explicit criteria for the properties required of a semiconductor nonlinear medium suitable for use in all-optical switching devices employing total internal reflection. Transmission as a function of laser intensity and film thickness has been calculated using a realistic model for penetration of the evanescent beam under TIR conditions. Requirements based on these results include a large nonlinear refractive index, large index change at saturation and small absorption coefficient. We show that unlike previously-studied semimetals and narrow-gap semiconductors, Type-II superlattices such as InAs-GaSb and variable-overlap superlattices (variants of Type-II which include a spacer between the layer containing the conduction-band minimum and that containing the valence band maximum) such as InAs-AlSb-GaSb hold prospects for satisfying all of these requirements simultaneously. As the free carrier lifetime will have a crucial influence on device performance, we have initiated a systematic experimental study of electron-hole recombination in InAs-based superlattices. From degenerate and nondegenerate four-wave mixing experiments, we have also determined nonlinear optical coefficients as a function of difference frequency and intensity. An InAs-GaSb superlattice has been found to display a refractive index change of ≈ 0.1, as well as device figures of merit which slightly surpasses any previously reported for weakly-saturating nonlinearities at CO 2 wavelengths. It is anticipated that future experiments on Type-II superlattices with longer lifetimes may yield nearly two orders of magnitude additional improvement in the nonlinear refractive index.

scholarly journals All-optical switching using a new photonic crystal directional coupler

2015 ◽  
Vol 4 (1) ◽  
pp. 63 ◽  
Author(s):  
B. Vakili ◽  
S. Bahadori-Haghighi ◽  
R. Ghayour
Keyword(s):  
Refractive Index ◽  
Photonic Crystal ◽  
Communication Systems ◽  
Optical Switching ◽  
Directional Coupler ◽  
Refractive Index Change ◽  
Control Signal ◽  
Index Change ◽  
All Optical ◽  
All Optical Switching

In this paper all-optical switching in a new photonic crystal directional coupler is performed.  The structure of the switch consists of a directional coupler and a separate path for a control signal called “control waveguide”. In contrast to the former reported structures in which the directional couplers are made by removing a row of rods entirely, the directional coupler in our optical switch is constructed by two reduced-radius line-defect waveguides separated by the control waveguide. Furthermore, in our case the background material has the nonlinear Kerr property. Therefore, in the structure of this work, no frequency overlap occurs between the control waveguide mode and the directional coupler modes. It is shown that such a condition provides a very good isolation between the control and the probe signals at the output ports. In the control waveguide, nonlinear Kerr effect causes the required refractive index change by the presence of a high power control (pump) signal. Even and odd modes of the coupler are investigated by applying the distribution of the refractive index change in the nonlinear region of a super-cell so that a switching length of about 94 µm is obtained at the wavelength of 1.55 µm. Finally, all-optical switching of the 1.55 µm probe signal using a control signal at the wavelength of 1.3 µm, is simulated through the finite-difference time-domain method, where both signals are desirable in optical communication systems. A very high extinction ratio of 67 dB is achieved and the temporal characteristics of the switch are demonstrated.

Robust Exciton Polariton in a Quantum-Well Waveguide

1998 ◽  
Vol 536 ◽  
Author(s):  
M. Shirai ◽  
K. Hosomi ◽  
T. Mishima ◽  
T. Katsuyama
Keyword(s):  
Refractive Index ◽  
Quantum Well ◽  
Temperature Dependence ◽  
Light Propagation ◽  
Directional Coupler ◽  
Refractive Index Change ◽  
Driving Voltage ◽  
Single Quantum Well ◽  
Index Change ◽  
Switching Devices

AbstractThe refractive index change of polariton propagation in a GaAs quantum-well waveguide was measured as a function of the electric field. Its temperature dependence was also measured. The experimental results showed that the refractive index change of the polariton propagation was at least three times as large as that of the conventional light propagation. This effect remains up to 40 K, and coincides with the temperature dependence of the rate of polariton scattering by phonons. We also Fabricated directional-coupler-type switching devices to apply this large refractive index change, and were able to demonstrate the operation in a single quantum-well waveguide. Our results indicate that extremely small and low driving voltage switching devices may be feasible.

scholarly journals Critical angle reflection imaging for quantification of molecular interactions on glass surface

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guangzhong Ma ◽  
Runli Liang ◽  
Zijian Wan ◽  
Shaopeng Wang
Keyword(s):  
Refractive Index ◽  
Small Molecule ◽  
Molecular Interactions ◽  
Glass Surface ◽  
Critical Angle ◽  
Dynamic Range ◽  
Refractive Index Change ◽  
Label Free ◽  
Index Change ◽  
Sensing Range

AbstractQuantification of molecular interactions on a surface is typically achieved via label-free techniques such as surface plasmon resonance (SPR). The sensitivity of SPR originates from the characteristic that the SPR angle is sensitive to the surface refractive index change. Analogously, in another interfacial optical phenomenon, total internal reflection, the critical angle is also refractive index dependent. Therefore, surface refractive index change can also be quantified by measuring the reflectivity near the critical angle. Based on this concept, we develop a method called critical angle reflection (CAR) imaging to quantify molecular interactions on glass surface. CAR imaging can be performed on SPR imaging setups. Through a side-by-side comparison, we show that CAR is capable of most molecular interaction measurements that SPR performs, including proteins, nucleic acids and cell-based detections. In addition, we show that CAR can detect small molecule bindings and intracellular signals beyond SPR sensing range. CAR exhibits several distinct characteristics, including tunable sensitivity and dynamic range, deeper vertical sensing range, fluorescence compatibility, broader wavelength and polarization of light selection, and glass surface chemistry. We anticipate CAR can expand SPR′s capability in small molecule detection, whole cell-based detection, simultaneous fluorescence imaging, and broader conjugation chemistry.

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