scholarly journals Electrostatically Tuned Optical Filters Based on Hybrid Plasmonic-Dielectric Thin Films for Hyperspectral Imaging

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 767
Author(s):  
Ahmed Abdelghfar ◽  
Mohamed A. Mousa ◽  
Bassant M. Fouad ◽  
Ahmed H. Saad ◽  
Noha Anous ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Optical Filter ◽  
Optical Filters ◽  
Medical Diagnostics ◽  
Visible Range ◽  
Crop Monitoring ◽  
Tunable Optical Filter ◽  
Wide Range ◽  
Fabry Perot ◽  
Maximum Transmission

Hyperspectral imaging has a wide range of uses, from medical diagnostics to crop monitoring; however, conventional hyperspectral imaging systems are relatively slow, bulky, and rather costly. In this paper, we present an inexpensive, compact tunable optical filter for hyperspectral applications. The filter is based on a Fabry-Pérot interferometer utilizing hybrid metallic-dielectric mirrors and actuated using a MEMS electrostatic actuator. The optical filter is designed using the transfer matrix method; then, the results were verified by an electromagnetic wave simulator. The actuator is based on a ring-shaped parallel plate capacitor and is designed using COMSOL Multiphysics. An actuation displacement of 170 nm was used, which is the required distance to tune the filter over the whole visible range (400–700 nm). There are two designs proposed for the optical filter: the first was optimized to provide maximum transmission and the other is optimized to have minimum full-width-half-maximum (FWHM) value. The first design has a maximum transmission percentage of 94.45% and a minimum transmission of 86.34%; while the minimum FWHM design had an average FWHM value of 7.267 nm. The results showed improvements over the current commercial filters both in transmission and in bandwidth.

Electrically tunable optical filter for infrared wavelength using liquid crystals in a Fabry–Perot étalon

1990 ◽  
Vol 57 (17) ◽  
pp. 1718-1720 ◽  
Author(s):  
J. S. Patel ◽  
M. A. Saifi ◽  
D. W. Berreman ◽  
Chinlon Lin ◽  
N. Andreadakis ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Optical Filter ◽  
Infrared Wavelength ◽  
Tunable Optical Filter ◽  
Fabry Perot

scholarly journals Thermo-Optic Tunable Optical Filter Based on Fabry-Perot Microcavities in SOI

2012 ◽  
Vol 6-7 ◽  
pp. 194-199
Author(s):  
Zhe Li ◽  
Hua Juan Qi ◽  
Yong Chuan Xiao ◽  
Feng Li Gao
Keyword(s):  
Refractive Index ◽  
Wavelength Division Multiplexing ◽  
Optical Filter ◽  
Silicon On Insulator ◽  
Central Wavelength ◽  
Wavelength Division ◽  
Tunable Optical Filter ◽  
Compact Size ◽  
Fabry Perot ◽  
Output Characteristics

An integrated TOF (Tunable Optical Filter) based on thermo-optic effect in Silicon on insulator (SOI) rib waveguide is designed and simulated. The device is comprised of two high refractivity contrast Si/Air stacks, functioning as high reflectivity of DBRs and separated by a variable refractive index Si F-P cavity. The output characteristics are calculated and simulated based on Transfer Matrix Method (TMM). Wavelength tuning is achieved through thermal modulation of refractive variation of the cavity.As the cavity Si is heated,the refractive index of the cavity increases.When the temperature of cavity Si changes within100°C，the central wavelength gets a continuous 8nm shift from 1550nm to 1558nm, which is right located in the WDM (Wavelength division multiplexing) networks operating at C-band. Moreover, by calculating, the tuning sensitivity is about 0.08nm/°C. Owing to the compact size and excellent characteristics of integration, the proposed component has a promising utilization in spectroscopy and optical communication.

Design of thermo-optic tunable optical filter based on Si/Air DBR and polymer Fabry–Perot microcavity in SOI

Optik ◽  
2014 ◽  
Vol 125 (12) ◽  
pp. 2885-2890 ◽  
Author(s):  
Kui Wu ◽  
Zhe Li ◽  
Jing Guo ◽  
Yongchuan Xiao ◽  
Huajuan Qi ◽  
...  
Keyword(s):  
Optical Filter ◽  
Tunable Optical Filter ◽  
Fabry Perot

Wavelength and throughput tuning of FORR-based optical filter using Sagnac effect

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Fahimeh Rezazadeh ◽  
Faramarz E. Seraji ◽  
Mohammad Ghanbarisabagh
Keyword(s):  
Ring Resonator ◽  
Fiber Optic ◽  
Free Spectral Range ◽  
Optical Filter ◽  
Paper Analysis ◽  
Sagnac Effect ◽  
Tunable Optical Filter ◽  
The Difference ◽  
Maximum Transmission ◽  
Filter Response

Abstract In this paper, analysis of tunable optical filter based on Sagnac effect tuning is presented using a fiber-optic ring resonator (FORR) and the responses of the filters for different FORR and Sagnac loop parameters under steady-state conditions are investigated. Formulation of the optical filter response is presented by considering with/without single and multiple Sagnac loop effects. Effects of the FORR parameters of filter response are studied and analyzed under different parametric conditions for the maximum transmission intensity. The simulation results show that the filter responses are affected strongly by the Sagnac loop and the FORR parameters. With the Sagnac effect, it is shown that full-width at half maximum (FWHM) would increase by increasing the phase difference Δϕ from 0 to 0.20 radian, beyond which it will start decreasing. The difference in FWHM value in this range of Δϕ variations is found to be about 3.77 nm. Between the first and the second resonances at wavelengths 1395 and 1538 nm, the free spectral range (FSR) is found to be 140 nm. In multiple loops effects, by increasing the number of loop turn N, the values of FSR would reduce. For Δϕ = 0.3 and N = 1,  2,  3, the values of FSR are obtained as 144, 74, 47 nm, respectively.

Tunable optical filter based on liquid crystal Fabry-Perot etalon

2004 ◽  
Author(s):  
Haixing Chen ◽  
Tengchao Huang ◽  
Weidong Shen ◽  
Haifeng Li ◽  
Peifu Gu
Keyword(s):  
Liquid Crystal ◽  
Optical Filter ◽  
Tunable Optical Filter ◽  
Fabry Perot

scholarly journals Dichroic Circular Polarizers Based on Plasmonics for Polarization Imaging Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2145
Author(s):  
Junyan Zheng ◽  
Xin He ◽  
Paul Beckett ◽  
Xinjie Sun ◽  
Zixin Cai ◽  
...  
Keyword(s):  
Incident Light ◽  
Polarization State ◽  
Optical Loss ◽  
Optical Filters ◽  
Transmission Efficiency ◽  
Visible Range ◽  
Angle Of Incidence ◽  
Polarization Imaging ◽  
Visible Wavelengths ◽  
Maximum Transmission

Dichroic circular polarizers (DCP) represent an important group of optical filters that transfer only that part of the incident light with the desired polarization state and absorb the remainder. However, DCPs are usually bulky and exhibit significant optical loss. Moreover, the integration of these kinds of DCP devices can be difficult and costly as different compositions of chemicals are needed to achieve the desired polarization status. Circular polarizers based on metasurfaces require only thin films in the order of hundreds of nanometers but are limited by their sensitivity to angle of incidence. Furthermore, few existing solutions offer broadband operation in the visible range. By using computational simulations, this paper proposes and analyses a plasmonic DCP structure operating in the visible, from 400 nm to 700 nm which overcomes these drawbacks. The resulting circular dichroism transmission (CDT) is more than 0.9, and the maximum transmission efficiency is greater than 78% at visible wavelengths. These CDT characteristics are largely independent of angle of incidence up to angles of 80 degrees.

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