Mechanical Passive Compensation for Athermalisation Design of Infrared Optical System

2013 ◽  
Vol 552 ◽  
pp. 93-96
Author(s):  
Zhi Zhang ◽  
Zhao Hui Zhang ◽  
Zhe Yuan Fan ◽  
Aqi Yan ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Thermal Expansion ◽  
Optical System ◽  
Temperature Compensation ◽  
Refractive Index Change ◽  
Index Change ◽  
Aerospace Application ◽  
Temperature Range ◽  
Passive Compensation

Optical equipments especially those for aerospace application are expected to work over a wide temperature range. The change of temperature could cause the refractive index change of infrared glass elements. Furthermore, it would lead to the defocus of the image surface and the performance degradation, so the method of temperature compensation must be adopted, which could make sure that optical system would adapt to the change of ambient temperature. A method of temperature compensation with mechanical passive compensation is briefly described, and an example is also given. The quality of image could be optimized through mechanical passive compensation,depending on the differences of metal and non-metallic thermal expansion coefficient. The results show that the optical system works stablely in the designed temperature range. It is of great importance to the athermalisation design of infrared optical system.

scholarly journals Online optical refractive index measurement in research reactor core

2021 ◽  
Vol 253 ◽  
pp. 04020
Author(s):  
Gary Fourneau ◽  
Marion Agoyan ◽  
Guy Chemol ◽  
Ayoub Ladaci ◽  
Hicham Maskrot ◽  
...  
Keyword(s):  
Refractive Index ◽  
Fiber Optics ◽  
Optical System ◽  
Research Reactor ◽  
Refractive Index Change ◽  
Reactor Core ◽  
Optical Path ◽  
Refractive Index Measurement ◽  
Measuring Device ◽  
Index Change

There is a growing interest in fiber optic measurements for applications in radiation environments. Optical fiber sensors and diagnostics can monitor many parameters of interest inside a research reactor core. For some applications, fiber optics are combined with an optical system that collects or focuses the light beam. The Radiation-Induced-Refractive-Index-Change (RIRIC) of the used glasses appears then as major phenomenon as it is a determining value for the sensor optical function. In the framework of the development of a radiation hardened confocal chromatic sensor, we implemented an on-line refractive index measuring device in order to test in a reactor core various glasses, candidates to be implemented into the sensor. The measurement relies on interferometry, which is a challenge because of the small volume available, the impossibility to make optical adjustments once installed, and the high temperature of operation. Precisely, the quantity retrieved is the optical path (product of the length L by the optical refractive index n), when L is well known, we can deduce n. But under high neutron fluence, some variation in density can be observed. The targeted online measurement of the refractive index therefore becomes an optical path measurement. We will present the device, the principle of measurement, and the first results of some index change measurement, produced by a temperature ramp from 20 °C and 350 °C. We have obtained original data for most of the candidate glasses used to design the optical system.

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.

InP-based optical switch module operating through carrier-induced refractive index change

1990 ◽  
Vol 29 (3) ◽  
pp. 191 ◽  
Author(s):  
Takeshi Kato ◽  
Hiroaki Inoue ◽  
Yasushi Takahashi ◽  
Koji K. Ishida
Keyword(s):  
Refractive Index ◽  
Optical Switch ◽  
Refractive Index Change ◽  
Index Change ◽  
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