Thermally Activated Transmissive Optical Elements for Rejection of Laser Radiation

1994 ◽  
Vol 374 ◽  
Author(s):  
H. O. Marcy ◽  
L. F. Warren ◽  
P. H. Cunningham
Keyword(s):  
Large Fraction ◽  
Optical Power ◽  
Optical Element ◽  
Laser Pulses ◽  
Optical Systems ◽  
Incident Laser ◽  
Optical Elements ◽  
Thermally Activated ◽  
System A ◽  
Optical Power Limiting

AbstractThe sacrificial thermal shutter/reflector concept is suitable for optical power limiting in optical systems containing an intermediate focus and uses a thermally activated chemical process to form a mirror that reflects a large fraction of the incident laser light. Under normal illumination, the thermal reflector component is a transmissive optical element at or near a focal plane of an optical system. A pulse from an incident laser beam heats a film of precursor chemicals on the optical element and thereby converts it to a localized reflective metallic mirror. For visible laser pulses longer than 0.1 ms, the thermal shutter provides optical limiting at energies below the ANSI Maximum Permissible Exposure (MPE) standard for laser eye protection. For shorter pulses, near-MPE limiting is achieved. See-through during exposure is also possible with these elements. Various thermal shutter chemistries and efforts to form optically clear thin precursor films are described. The laser testing results highlight the importance of the substrate and absorber in these devices.

Simulation and Experimental Analysis of Moulding Processes of Glass Diffractive Optical Elements

2012 ◽  
Vol 217-219 ◽  
pp. 1646-1649 ◽  
Author(s):  
Chia Jung Chang ◽  
Choung Lii Chao ◽  
Wen Chen Chou ◽  
Yu Kun Chen ◽  
Kung Jeng Ma ◽  
...  
Keyword(s):  
Optical Element ◽  
Dimensional Accuracy ◽  
Optical Systems ◽  
Free Form ◽  
Market Demand ◽  
Optical Elements ◽  
Form Accuracy ◽  
Moulding Process ◽  
The Difference ◽  
Glass Lenses

Driven by the huge market demand, the glass lenses made of various optical glasses are required to be more diversified in sizes/shapes, to have better form accuracy/ surface roughness, to be more environmental durable, and to be more competitive in price. In comparison to conventional refractive lens, diffractive lens (diffractive optical element, DOE) has the advantages of being thinner and lighter, and is widely used in optical systems such as lighting and photovoltaic systems. Glass moulding process(GMP) is regarded as a very promising technique for mass producing high precision optical components such as spherical/ aspheric glass lenses and free-form optics. However, only a handful of materials can sustain the chemical reaction, mechanical stress and temperature involved in the glass moulding process. Besides, almost all of these mould materials are classified as hard-to-machine materials. This makes the machining of these materials to sub-micrometer form accuracy and nanometer surface finish a rather tough and expensive task. As a result, making service life of mould longer has played a critical part in the GMP industry. The excessive stress and/or temperature involved in the moulding process are amongst the main reasons for pre-matured mould failure. This research aimed to analyze the stress/strain conditions and the obtained dimensional accuracy under various molding parameters by simulations. Molding experiments were subsequently carried out to verify the simulated results. A glass DOE of 14.8 mm in diameter and 3.36 mm in thickness are successfully produced in this research and the difference between the simulated and the molded DOE is around 15μm.

Nonlinear transmittance and optical power limiting in magnesium ferrite nanoparticles: effects of laser pulsewidth and particle size

RSC Advances ◽  
2016 ◽  
Vol 6 (108) ◽  
pp. 106754-106761 ◽  
Author(s):  
Sreekanth Perumbilavil ◽  
Kishore Sridharan ◽  
Ann Rose Abraham ◽  
Harsha P. Janardhanan ◽  
Nandakumar Kalarikkal ◽  
...  
Keyword(s):  
Particle Size ◽  
Femtosecond Laser ◽  
Optical Power ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ferrite Nanoparticles ◽  
Magnesium Ferrite ◽  
Nonlinear Transmission ◽  
Size Dependent ◽  
Optical Power Limiting

We report comparative measurements of size dependent nonlinear transmission and optical power limiting in nanocrystalline magnesium ferrite (MgFe2O4) particles excited by short (nanosecond) and ultrashort (femtosecond) laser pulses.

PICOSECOND OPTICAL LIMITING PERFORMANCE OF A NOVEL PPV-ZnPc CONJUGATED POLYMER

2000 ◽  
Vol 09 (03) ◽  
pp. 289-296 ◽  
Author(s):  
JINGJIN YU ◽  
LIMING WANG ◽  
QING WANG ◽  
MANKIT NG ◽  
LUPING YU
Keyword(s):  
Conjugated Polymers ◽  
Time Scale ◽  
Conjugated Polymer ◽  
Optical Power ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Picosecond Time Scale ◽  
Backbone Modification ◽  
Optical Power Limiting ◽  
532 Nm

A novel ZnPc monomer as well as PPV-ZnPc conjugated polymers have been synthesized and their optical power limiting (OPL) performances toward picosecond laser pulses at 532 nm have been measured. The comparison with the performance of C 60 under the same condition indicates that two of the compounds synthesized outperformed C 60 at picosecond time scale. It was found that conjugated PPV polymers containing a small amount of ZnPc cannot only preserve, but have also showed improvement over the monomer's OPL properties. It is believed that the backbone modification was responsible for the enhanced OPL performance.

New organic nonlinear optical materials: dithienylethylenes

2001 ◽  
Vol 708 ◽  
Author(s):  
B. Sahraoui ◽  
K.J. Pluciński ◽  
I. V. Kityk ◽  
B. Paci ◽  
P. Baldeck ◽  
...  
Keyword(s):  
Optical Materials ◽  
Optical Power ◽  
Laser Pulses ◽  
Visible Range ◽  
Nanosecond Laser ◽  
Wave Mixing ◽  
Third Order ◽  
Nanosecond Laser Pulses ◽  
Optical Power Limiting ◽  
532 Nm

ABSTRACTMeasurements of the third-order susceptibilities of new dithienylethylenes in solutions using a degenerate four wave mixing technique at λ=532 nm in picosecond regime were made. From these measurements we deduced the second order hyperpolarizabilities. Optical power limiting properties of the mentioned compounds using nanosecond laser pulses in the visible range are evaluated. The dispersion of nonlinear absorption coefficients is obtained. The appropriate quantum chemical calculations are carried out.

scholarly journals MEMS-actuated metasurface Alvarez lens

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Zheyi Han ◽  
Shane Colburn ◽  
Arka Majumdar ◽  
Karl F. Böhringer
Keyword(s):  
Power Consumption ◽  
Tuning Range ◽  
Focal Length ◽  
Unit Cost ◽  
Optical Power ◽  
Optical Systems ◽  
Cubic Phase ◽  
Optical Elements ◽  
Essential Components ◽  
Wide Range

AbstractMiniature lenses with a tunable focus are essential components for many modern applications involving compact optical systems. While several tunable lenses have been reported with various tuning mechanisms, they often face challenges with respect to power consumption, tuning speed, fabrication cost, or production scalability. In this work, we have adapted the mechanism of an Alvarez lens – a varifocal composite lens in which lateral shifts of two optical elements with cubic phase surfaces give rise to a change in the optical power – to construct a miniature, microelectromechanical system (MEMS)-actuated metasurface Alvarez lens. Implementation based on an electrostatic MEMS generates fast and controllable actuation with low power consumption. The utilization of metasurfaces – ultrathin and subwavelength-patterned diffractive optics – as optical elements greatly reduces the device volume compared to systems using conventional freeform lenses. The entire MEMS Alvarez metalens is fully compatible with modern semiconductor fabrication technologies, granting it the potential to be mass-produced at a low unit cost. In the reported prototype operating at 1550 nm wavelength, a total uniaxial displacement of 6.3 µm was achieved in the Alvarez metalens with a direct-current (DC) voltage application up to 20 V, which modulated the focal position within a total tuning range of 68 µm, producing more than an order of magnitude change in the focal length and a 1460-diopter change in the optical power. The MEMS Alvarez metalens has a robust design that can potentially generate a much larger tuning range without substantially increasing the device volume or energy consumption, making it desirable for a wide range of imaging and display applications.

scholarly journals Measurement and correction of two-sided freeform optical elements with combined tactile-optical metrology equipment

2019 ◽  
Vol 215 ◽  
pp. 08002
Author(s):  
Johannes Hartung ◽  
Henrik von Lukowicz ◽  
Mathias Rohde ◽  
Knut Kleinbauer ◽  
Nils Heidler ◽  
...  
Keyword(s):  
Iterative Process ◽  
High Performance ◽  
State Of The Art ◽  
Optical Element ◽  
Optical Systems ◽  
Optical Metrology ◽  
Optical Elements ◽  
Process Chains ◽  
Correction Step ◽  
Very High

Freeform optical elements are state of the art for several years to fabricate very high performance optical systems with the necessity of, e.g., strong folding in mirror system or correction of typical asymmetric aberrations in mirror systems as well as lens systems. For freeform mirror systems, in particular for metal mirrors, the metrology is well understood and iterative process chains are well established. For transmission elements with a freeform surface on both sides, manufacturing, metrology, and correction for both sides in a parallel manner is quite difficult. The article presents a method to measure such an optical element and correct it with a well-defined correction step to have both sides in a well-defined position to each other.

High Power Testing of Optical Connectors

2002 ◽  
Author(s):  
Paola Furcas ◽  
Rosanna Pastorelli ◽  
Giulia Salmini ◽  
Massimo Vanzi
Keyword(s):  
High Power ◽  
Optical Power ◽  
Environmental Issues ◽  
Optical Elements ◽  
Extraction Procedures ◽  
Equipment Operation ◽  
Burn Out ◽  
Power Testing

Abstract High optical power is considered as the source of failures in passive optical elements. Optical connectors, in particular, have been studied because of the unavoidable exposure of their optical interfaces to environmental issues during insertion and extraction. Cleaning and insertion/extraction procedures are investigated. Evidence for burn-out, depending on the different procedures, calls for new suitable rules for handling during equipment operation and testing.

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