scholarly journals Observation of nonlinear dynamics in an optical levitation system

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Jinyong Ma ◽  
Jiayi Qin ◽  
Geoff T. Campbell ◽  
Giovanni Guccione ◽  
Ruvi Lecamwasam ◽  
...  
Keyword(s):  
Optical Cavity ◽  
Mechanical Quality Factor ◽  
Optical Field ◽  
Free Standing ◽  
Levitation System ◽  
Active Feedback ◽  
Sideband Generation ◽  
Optical Levitation ◽  
Mechanical Oscillators ◽  
Lift Off

Abstract Optical levitation of mechanical oscillators has been suggested as a promising way to decouple the environmental noise and increase the mechanical quality factor. Here, we investigate the dynamics of a free-standing mirror acting as the top reflector of a vertical optical cavity, designed as a testbed for a tripod cavity optical levitation setup. To reach the regime of levitation for a milligram-scale mirror, the optical intensity of the intracavity optical field approaches 3 MW cm−2. We identify three distinct optomechanical effects: excitation of acoustic vibrations, expansion due to photothermal absorption, and partial lift-off of the mirror due to radiation pressure force. These effects are intercoupled via the intracavity optical field and induce complex system dynamics inclusive of high-order sideband generation, optical bistability, parametric amplification, and the optical spring effect. We modify the response of the mirror with active feedback control to improve the overall stability of the system.

Optical brake induced by laser shock waves

2021 ◽  
pp. 2050010
Author(s):  
Qiao Kang ◽  
Dongyi Shen ◽  
Jie Sun ◽  
Xin Luo ◽  
Wei Liu ◽  
...  
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Optical Method ◽  
Close Contact ◽  
Surface Friction ◽  
Laser Shock ◽  
Free Standing ◽  
Friction Forces ◽  
Optical Levitation ◽  
Contact Surfaces

We demonstrate an optical method to modify friction forces between two close-contact surfaces through laser-induced shock waves, which can strongly enhance surface friction forces in a sandwiched confinement with/without lubricant, due to the increase of pressure arising from excited shock waves. Such enhanced friction can even lead to a rotating rotor’s braking effect. Meanwhile, this shock wave-modified friction force is found to decrease under a free-standing configuration. This technique of optically controllable friction may pave the way for applications in optical levitation, transportation, and microfluidics.

Pt Schottky contacts on Ga- and N-face surfaces of free-standing GaN

2001 ◽  
Vol 680 ◽  
Author(s):  
U. Karrer ◽  
C.R. Miskys ◽  
O. Ambacher ◽  
M. Stutzmann
Keyword(s):  
Schottky Diodes ◽  
Reverse Current ◽  
Forward Direction ◽  
Hydride Vapor Phase Epitaxy ◽  
Free Standing ◽  
Band Bending ◽  
Barrier Heights ◽  
Consistent Solution ◽  
Lift Off ◽  
Gap States

ABSTRACTThick GaN films, grown by hydride vapor phase epitaxy (HVPE), were separated from their sapphire substrate with a laser-induced lift-off process. After cleaning and polishing, these films offer the most direct way to investigate and compare the influence of crystal polarity on the electronic properties of Ga-face and N-face surfaces, respectively. Different barrier heights for Pt Schottky diodes evaporated onto Ga- and N-face GaN are determined from the dependence of the effective barrier height versus ideality factor by I-V measurements to 1.15 eV and 0.80 eV, respectively. The charge neutrality condition at the surface is modified by the spontaneous polarization due to the polarization induced bound sheet charge. This effect has to be included in the electronegativity concept of metal induced gap states (MIGS) and can also be illustrated by different band bending of the conduction and valence band, inferred from the self-consistent solution of the Schrödinger-Poisson equation. Furthermore, temperature dependent I-V characteristics are compared to simulated behavior of Schottky diodes, exhibiting excellent agreement in forward direction, but showing deviations in the reverse current.

Bending in HVPE GaN free-standing films: effects of laser lift-off, polishing and high-pressure annealing

2006 ◽  
Vol 3 (6) ◽  
pp. 1475-1478 ◽  
Author(s):  
T. Paskova ◽  
V. Darakchieva ◽  
P. P. Paskov ◽  
B. Monemar ◽  
M. Bukowski ◽  
...  
Keyword(s):  
High Pressure ◽  
Free Standing ◽  
Lift Off

A nitrogen doped low-dislocation density free-standing single crystal diamond plate fabricated by a lift-off process

2014 ◽  
Vol 104 (25) ◽  
pp. 252109 ◽  
Author(s):  
Yoshiaki Mokuno ◽  
Yukako Kato ◽  
Nobuteru Tsubouchi ◽  
Akiyoshi Chayahara ◽  
Hideaki Yamada ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Single Crystal ◽  
Free Standing ◽  
Nitrogen Doped ◽  
Diamond Plate ◽  
Low Dislocation Density ◽  
Single Crystal Diamond ◽  
Lift Off

Free-standing GaN substrates fabricated by a combination of substrate fracturing and chemical lift-off

2011 ◽  
Vol 8 (7-8) ◽  
pp. 2123-2126 ◽  
Author(s):  
Hiroki Goto ◽  
Hyun-Jae Lee ◽  
Seogwoo Lee ◽  
Meoung-Whan Cho ◽  
Takafumi Yao
Keyword(s):  
Free Standing ◽  
Lift Off

scholarly journals Femtosecond Laser Lift‐Off with Sub‐Bandgap Excitation for Production of Free‐Standing GaN Light‐Emitting Diode Chips

2019 ◽  
Vol 22 (2) ◽  
pp. 1901192 ◽  
Author(s):  
Steffen Bornemann ◽  
Nursidik Yulianto ◽  
Hendrik Spende ◽  
Yuliati Herbani ◽  
Joan Daniel Prades ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Light Emitting Diode ◽  
Free Standing ◽  
Light Emitting ◽  
Lift Off

Densification kinetics of glass films constrained on rigid substrates

1995 ◽  
Vol 10 (5) ◽  
pp. 1321-1326 ◽  
Author(s):  
Jaecheol Bang ◽  
Guo-Quan Lu
Keyword(s):  
Polyvinyl Butyral ◽  
Silica Content ◽  
Free Standing ◽  
Free Film ◽  
Lift Off ◽  
Free Films ◽  
Mylar Sheet ◽  
Blade Casting ◽  
Kinetics Of

The kinetics of constrained-film sintering were studied in a borosilicate glass (BSG) + silica system because of their applications in microelectronic packaging technologies. Samples with a silica content by 20% by volume were prepared from slurries of powder mixtures in a commercial polyvinyl butyral (PVB) binder solution. Constrained films about 0.2 mm thick were formed by doctor-blade casting the slurries on silicon wafers. Free-standing films about 0.6 mm thick were also produced by casting the slurries on a treated mylar sheet for easy lift-off. Sintering experiments were carried out in a hot stage at temperatures between 715 °C and 775 °C. Shrinkage profiles of the free and constrained (shrinkage in thickness only) films were determined in situ using a custom-designed optical system. The densification rates measured in the constrained films were slower than those in the free films. However, the substrate constraint had no effect on the activation energy of densification which was found equal to 385 ± 10 kJ/mol, the same for both free and constrained films. A relation between the constrained-film and free-film densification profiles was derived using the viscous analogy for the constitutive equations of a porous sintering body.

scholarly journals Lift-off of Free-standing Layers in the Kerfless Porous Silicon Process

2013 ◽  
Vol 38 ◽  
pp. 919-925 ◽  
Author(s):  
Sarah Kajari-Schröder ◽  
Jörg Käsewieter ◽  
Jan Hensen ◽  
Rolf Brendel
Keyword(s):  
Porous Silicon ◽  
Free Standing ◽  
Lift Off
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