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  1. Article ; Online: Silicon Oxy-Nitride for the Low Refractive Index Layers in the Mirror Coatings of the Cryogenic Laser Interferometer Gravitational Waves Detector.

    Chao, Shiuh / Tsai, Wen-Jie / Tsai, Dong-Lin / Chang, I-Peng / Hong, Qian-Yi / Chang, Wei-Chih / Kao, Yu-Hsun

    Physical review letters

    2023  Volume 130, Issue 8, Page(s) 81403

    Abstract: The low refractive index layers in the mirror coatings of the room-temperature laser interferometer gravitational waves detectors are silica deposited by the ion beam sputter method. However, the silica film suffers from the cryogenic mechanical loss ... ...

    Abstract The low refractive index layers in the mirror coatings of the room-temperature laser interferometer gravitational waves detectors are silica deposited by the ion beam sputter method. However, the silica film suffers from the cryogenic mechanical loss peak, hindering its application for the next generation detector operated at cryogenics. New low refractive index materials need to be explored. We study amorphous silicon oxy-nitride (SiON) films deposited using the method of plasma-enhanced chemical vapor deposition. By changing the N_{2}O/SiH_{4} flow rate ratio, we can tune the refractive index of the SiON smoothly from nitridelike to silicalike of ∼1.48 at 1064 nm, 1550 nm, and 1950 nm. Thermal anneal reduced the refractive index down to ∼1.46 and effectively reduced the absorption and cryogenic mechanical loss; the reductions correlated with the N─H bond concentration decrease. Extinction coefficients of the SiONs at the three wavelengths are reduced down to 5×10^{-6}∼3×10^{-7} by annealing. Cryogenic mechanical losses at 10 K and 20 K (for ET and KAGRA) of the annealed SiONs are significantly lower than the annealed ion beam sputter silica. They are comparable at 120 K (for LIGO-Voyager). Absorption from the vibrational modes of the N─H terminal-hydride structures dominates over the absorption from other terminal hydrides, the Urbach tail, and the silicon dangling bond states in SiON at the three wavelengths.
    Language English
    Publishing date 2023-03-09
    Publishing country United States
    Document type Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.130.081403
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Low cryogenic mechanical loss composite silica thin film for low thermal noise dielectric mirror coatings.

    Kuo, Ling-Chi / Pan, Huang-Wei / Chang, Chi-Li / Chao, Shiuh

    Optics letters

    2019  Volume 44, Issue 2, Page(s) 247–250

    Abstract: Thermal noise in dielectric mirror-coatings is the limiting factor for ultra-high-precision metrologies employing optical cavities and being operated at cryogenic temperatures. Silica film is an indispensable low-refractive-index material for mirror ... ...

    Abstract Thermal noise in dielectric mirror-coatings is the limiting factor for ultra-high-precision metrologies employing optical cavities and being operated at cryogenic temperatures. Silica film is an indispensable low-refractive-index material for mirror coatings but suffers from high cryogenic mechanical loss and hence contributes to high thermal noise. We partitioned a thick silica film into thin layers by introducing blocking layers of titania. The cryogenic mechanical loss of silica was significantly suppressed; the effect was more profound for thinner partitions. Elimination of the transitions of the long-range two-level systems with scales that exceed the thickness of the silica partition is hypothesized. Dielectric mirror coatings with blocking layers are proposed to reduce the cryogenic thermal noise of the coatings. The calculated reflectance spectrum is consistent with that of the conventional quarter-wave (QW) stack around 1550 nm, and the calculated absorptance increases 2.2 times over that of a conventional titania/silica QW stack where the titania is absorptive.
    Language English
    Publishing date 2019-01-15
    Publishing country United States
    Document type Journal Article
    ISSN 1539-4794
    ISSN (online) 1539-4794
    DOI 10.1364/OL.44.000247
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Spectral shift by half free-spectral-range for microring resonator employing the phase jump phenomenon in coupled-waveguide and application on all-microring wavelength interleaver.

    Shih, Chih T'sung / Chao, Shiuh

    Optics express

    2009  Volume 17, Issue 10, Page(s) 7756–7770

    Abstract: Using coupled-mode theory, we have shown that there is a pi phase jump between the input and the through/drop fields of a codirectional coupler when the gap width between the coupled-waveguides reaches certain values such that the length of the coupler ... ...

    Abstract Using coupled-mode theory, we have shown that there is a pi phase jump between the input and the through/drop fields of a codirectional coupler when the gap width between the coupled-waveguides reaches certain values such that the length of the coupler equals to the odd integer (for through field) or even integer (for drop field) times of the Transfer Distance. We introduced an efficient numerical method based on combining the scattering matrix method and FDTD method for analyzing a microring that has material loss. By applying this method, we found that the phase jump phenomenon also occurs in a half-ring coupler when the gap width between the coupled half-ring waveguides reaches a critical value. We showed that, for a given operating bandwidth, it is important that the gap width between the rings has to be larger than a certain value in order to avoid the phase jump, or smaller in order to take advantage of the phase jump. Based on the phase jump phenomenon, we found that the through and the drop spectra of the single-arm and the double-arm microring can be manipulated to shift about one half free spectral range by selecting appropriate gap widths. A novel all-microring wavelength interleaver, based on the phase jump phenomenon, is proposed and numerically demonstrated.
    Language English
    Publishing date 2009-04-12
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/oe.17.007756
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Fabrication of three-dimensional autocloned photonic crystal on sapphire substrate.

    Ku, Hao Ming / Huang, Chen Yang / Chao, Shiuh

    Applied optics

    2011  Volume 50, Issue 9, Page(s) C1–4

    Abstract: We applied the laser interference lithography method to form a patterned sapphire substrate (PSS). A three-dimensional photonic crystal was formed by autocloning the PSS with alternate Ta2O5/SiO2 coatings. A high total integrated reflectance (TIR) band ... ...

    Abstract We applied the laser interference lithography method to form a patterned sapphire substrate (PSS). A three-dimensional photonic crystal was formed by autocloning the PSS with alternate Ta2O5/SiO2 coatings. A high total integrated reflectance (TIR) band was obtained around the 410 to 470 nm wavelength range that matched the emission spectrum of the gallium nitride (GaN) light-emitting diode (LED) for application in manipulating the light extraction of the sapphire-based GaN LED.
    Language English
    Publishing date 2011-03-20
    Publishing country United States
    Document type Journal Article
    ISSN 1539-4522
    ISSN (online) 1539-4522
    DOI 10.1364/AO.50.0000C1
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: A compact optical pickup head in blue wavelength with high horizontal stability for laser thermal lithography.

    Lee, Yuan-Chin / Chao, Shiuh / Huang, Chun-Chieh / Cheng, Kuen-Chiuan

    Optics express

    2013  Volume 21, Issue 20, Page(s) 23556–23567

    Abstract: A compact optical pickup head in blue wavelength with a single-axial actuator i.e. focusing, for laser thermal lithography was designed, fabricated, and tested. The numerical aperture of the objective lens was 0.85. The linear range of the focus error ... ...

    Abstract A compact optical pickup head in blue wavelength with a single-axial actuator i.e. focusing, for laser thermal lithography was designed, fabricated, and tested. The numerical aperture of the objective lens was 0.85. The linear range of the focus error signal was 3 μm. A planar spring structure for improving the horizontal stability was designed and incorporated into the actuator. We applied a modified push-pull method together with a static Blu-ray re-writable disc to test the horizontal stability of the pickup head. We found that the in-plane jitter of the pickup head in two orthogonal directions were 0.34 nm and 1.59 nm, respectively. We demonstrated an example of applying the pickup head to write an inorganic photo-resist GeSbSnO film, and well-defined pattern was obtained with ~220 nm spot size.
    Language English
    Publishing date 2013-10-07
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.21.023556
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Light extraction enhancement for InGaN/GaN LED by three dimensional auto-cloned photonics crystal.

    Huang, Chen-Yang / Ku, Hao-Min / Chao, Shiuh

    Optics express

    2009  Volume 17, Issue 26, Page(s) 23702–23711

    Abstract: Three dimensional (3-D) auto-cloned photonics crystal (APhC) of Ta2O5/SiO2 multi-layers was fabricated on the backside of the sapphire wafer that had InGaN/GaN multi-quantum well LED on the front side. 94% light extraction enhancement in comparison to ... ...

    Abstract Three dimensional (3-D) auto-cloned photonics crystal (APhC) of Ta2O5/SiO2 multi-layers was fabricated on the backside of the sapphire wafer that had InGaN/GaN multi-quantum well LED on the front side. 94% light extraction enhancement in comparison to the LED without APhC was obtained. Electrical properties of the LED did not altered by the APhC and its fabrication process. Experimental evidences showed that light extraction enhancement mechanism is two-folded: for rays that are emitted from the source and incident at lower angle of incidence to the APhC, the APhC acts as a high reflector; for rays incident at higher angle of incidence to the APhC, first order diffracted light from the APhC appears, the diffracted light is concentrated around the surface normal and is therefore capable of escaping.
    MeSH term(s) Computer-Aided Design ; Crystallization/methods ; Equipment Design ; Equipment Failure Analysis ; Gallium/chemistry ; Indium/chemistry ; Lighting/instrumentation ; Photons ; Semiconductors
    Chemical Substances Indium (045A6V3VFX) ; gallium nitride (1R9CC3P9VL) ; Gallium (CH46OC8YV4) ; indium nitride (D66UAC005A)
    Language English
    Publishing date 2009-12-21
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.17.023702
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Simple design method for third-order dispersion compensation with a thin-film dispersion compensator.

    Liu, Jiayu / Chao, Shiuh

    Applied optics

    2003  Volume 43, Issue 17, Page(s) 3442–3448

    Abstract: A novel and simple numerical method for finding the best thin-film structures for third-order dispersion compensation has been achieved. A target third-order dispersion value is specified first; then the multilayer thin-film structure is optimized to ... ...

    Abstract A novel and simple numerical method for finding the best thin-film structures for third-order dispersion compensation has been achieved. A target third-order dispersion value is specified first; then the multilayer thin-film structure is optimized to have a second-order dispersion spectrum, which has the least deviation from linearity and has a slope that equals the specified third-order dispersion value. Numerical examples are presented for reflection-type and transmission-type thin-film compensators. Both types can achieve required phase compensation, but the reflection type has a flatter amplitude response than the transmission type.
    Language English
    Publishing date 2003-11-24
    Publishing country United States
    Document type Journal Article
    ISSN 1559-128X
    ISSN 1559-128X
    DOI 10.1364/ao.43.003442
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Surface profile control of the autocloned photonic crystal by ion-beam-sputter deposition with radio-frequency-bias etching.

    Huang, Chen Yang / Min Ku, Hao / Chao, Shiuh

    Applied optics

    2008  Volume 48, Issue 1, Page(s) 69–73

    Abstract: Growth of the autocloned Ta(2)O(5)/SiO(2) multilayer photonic crystal with a lateral sawtooth period was simulated. Ion-beam sputter (IBS) was applied to deposit the films and radio-frequency-bias (RF-bias) etching was applied simultaneously with the IBS ...

    Abstract Growth of the autocloned Ta(2)O(5)/SiO(2) multilayer photonic crystal with a lateral sawtooth period was simulated. Ion-beam sputter (IBS) was applied to deposit the films and radio-frequency-bias (RF-bias) etching was applied simultaneously with the IBS on the Ta(2)O(5) film. Both simulation and experiment showed that the quality of the autocloning can be controlled by the RF-bias power; there is an intermediate power range within which the drop of peak-to-valley height variation of the sawtooth profile can be reduced significantly such that a high degree of autocloning can be achieved. Analysis showed that simultaneous deposition and etching at the proper RF-bias power on the Ta(2)O(5) film has the capability to compensate the flattening effect of the SiO(2) deposition such that the sawtooth surface profile can be maintained.
    Language English
    Publishing date 2008-09-25
    Publishing country United States
    Document type Journal Article
    ISSN 1539-4522
    ISSN (online) 1539-4522
    DOI 10.1364/ao.48.000069
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: MQWs InGaN/GaN LED with embedded micro-mirror array in the epitaxial-lateral-overgrowth gallium nitride for light extraction enhancement.

    Huang, Chen-Yang / Ku, Hao-Min / Liao, Chen-Zi / Chao, Shiuh

    Optics express

    2010  Volume 18, Issue 10, Page(s) 10674–10684

    Abstract: Multi-quantum wells (MQWs) InGaN/GaN LEDs, 300 microm x 300 microm chip size, were fabricated with Ta(2)O(5) / SiO(2) dielectric multi-layer micro-mirror array (MMA) embedded in the epitaxiallateral- overgrowth (ELOG) gallium nitride (GaN) on the c-plane ...

    Abstract Multi-quantum wells (MQWs) InGaN/GaN LEDs, 300 microm x 300 microm chip size, were fabricated with Ta(2)O(5) / SiO(2) dielectric multi-layer micro-mirror array (MMA) embedded in the epitaxiallateral- overgrowth (ELOG) gallium nitride (GaN) on the c-plane sapphire substrate. MQWs InGaN/GaN LEDs with ELOG embedded patterned SiO(2) array (P-SiO(2)) of the same dimension as the MMA were also fabricated for comparison. Dislocation density was reduced for the ELOG samples. 75.2% light extraction enhancement for P-SiO(2)-LED and 102.6% light extraction enhancement for MMA-LED were obtained over the standard LED. We showed that multiple-diffraction with high intensity from the MMA redirected the trap lights to escape from the LED causing the light extraction enhancement.
    MeSH term(s) Crystallization/methods ; Gallium/chemistry ; Lenses ; Light ; Lighting/instrumentation ; Miniaturization ; Scattering, Radiation ; Semiconductors
    Chemical Substances gallium nitride (1R9CC3P9VL) ; Gallium (CH46OC8YV4)
    Language English
    Publishing date 2010-05-10
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.18.010674
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Humidity effect on the decay of second-order nonlinearity in thermally poled fused silica.

    Chen, Huai-Yi / Chang, Feng-Fan / Liao, Jia-Cheng / Chao, Shiuh

    Optics express

    2009  Volume 14, Issue 25, Page(s) 12334–12340

    Abstract: Type I (GE124) and Type II (KV) fused silica were thermally poled in a vacuum and in air under identical poling conditions. Second-order nonlinear (SON) strength and nonlinear depth were found all to be the same. Samples were then stored in high and low ... ...

    Abstract Type I (GE124) and Type II (KV) fused silica were thermally poled in a vacuum and in air under identical poling conditions. Second-order nonlinear (SON) strength and nonlinear depth were found all to be the same. Samples were then stored in high and low humidity to study their SON stability. The SON of poled GE124 was stable over time despite different poling atmospheres and humidity in storage. The SON of both the air-poled and vacuum-poled KV samples decayed over time in both low and high humidity, with the exception that the air-poled KV sample stored in low humidity remained stable. High humidity accelerated the decay process of the KV samples. A porous surface model was used to interpret the decay mechanism. The decay curves implied multiple carriers or a multiple-porosity model for the decay mechanism.
    Language English
    Publishing date 2009-08-08
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/oe.14.012334
    Database MEDical Literature Analysis and Retrieval System OnLINE

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