Thermal management in planar optical systems with active components

1997 ◽  
Author(s):  
Christiane Gimkiewicz ◽  
Juergen Jahns
Keyword(s):  
Thermal Management ◽  
Optical Systems ◽  
Active Components

Pumped Liquid Multiphase Cooling

2004 ◽  
Author(s):  
Robert Hannemann ◽  
Joseph Marsala ◽  
Martin Pitasi
Keyword(s):  
Energy Efficiency ◽  
Thermal Management ◽  
Experimental Results ◽  
Optical Systems ◽  
Performance Limits ◽  
Working Fluids ◽  
Conventional Cooling ◽  
Management Capabilities ◽  
Very High

The performance limits of conventional cooling technologies are being reached in both military and commercial electronics and electro-optical systems. Pumped Liquid Multiphase Cooling (PLMC) provides significantly enhanced thermal management capabilities for these systems using mostly-conventional components and working fluids. PLMC is highly scalable and reliable. Energy efficiency is very high, surpassing conventional techniques by up to two orders of magnitude. This paper describes the basic PLMC technology and presents experimental results from several prototype embodiments of the technology.

scholarly journals Optimizing optical systems with active components

2012 ◽  
Author(s):  
Tibor Agócs ◽  
Lars Venema ◽  
Visa Korkiakoski ◽  
Gabby Kroes
Keyword(s):  
Optical Systems ◽  
Active Components

Development of a Hybrid PCM-Air Heat Sink

2011 ◽  
Author(s):  
Y. Kozak ◽  
B. Abramzon ◽  
G. Ziskind
Keyword(s):  
Melting Temperature ◽  
Thermal Management ◽  
Heat Sink ◽  
Power Dissipation ◽  
Phase Change Materials ◽  
Ambient Air ◽  
Significant Rise ◽  
Optical Systems ◽  
Base Temperature ◽  
Periodic Regime

The present study deals with the transient thermal management of electro-optical equipment using the phase-change materials (PCMs). These materials can absorb large amounts of heat without significant rise of their temperature during the melting process. This effect is attractive for using in the passive thermal management of portable electro-optical systems, particularly those where the device is intended to operate in the periodic regime, or where the relatively short stages of high power dissipation are followed by long stand-by periods without a considerable power release. In the present work, a so-called hybrid heat sink is developed. The heat sink is made of aluminum. The heat is dissipated on the heat sink base, and then is transferred by thermal conduction to the PCM and to a standard forced-convection air heat sink cooled by an attached fan. The whole system may be initially at some constant temperature which is below the PCM melting temperature. Then, power dissipation on the heat sink base is turned on. As heat propagates within the heat sink, some part of it is absorbed by the PCM causing a delay in the temperature growth at the heat sink base. Alternatively, the steady-state conditions may be such that the base temperature is below the PCM melting temperature, meaning that all the heat generated on the heat sink base is transferred to the cooling air. Then, the fan is turned off reducing the heat transfer to the ambient air, and the heat is absorbed into the PCM resulting in its melting. In both cases, the time that it will take the heat sink base to approach some specified maximum allowed temperature is expected to be longer than that without the PCM.

scholarly journals Effective Optical System Assembly Using Ultra-Precise Manufactured References

2020 ◽  
Vol 14 (4) ◽  
pp. 644-653
Author(s):  
Andreas Gebhardt ◽  
Matthias Beier ◽  
Erik Schmidt ◽  
Thomas Rendel ◽  
Ute Gawronski ◽  
...  
Keyword(s):  
Optical System ◽  
Laser Diodes ◽  
Optical Component ◽  
Machining Process ◽  
Optical Systems ◽  
Active Components ◽  
High Quality ◽  
Diamond Machining ◽  
Position And Orientation ◽  
Aspherical Lenses

The present work demonstrates that exactly manufactured references for joining, mounting, and metrology purposes are crucial in the effective assembly of high-quality optical systems. Based on the alignment turning of spherical and aspherical lenses, the proposed approach can be transferred to non-rotational symmetric elements such as prisms, active components (e.g., laser diodes), and freeform mirrors. The complexity of the optical component decides whether on-machine metrology or specific measurement setups need to be used to determine the position and orientation of the references with respect to the optical function. The resulting correction data are considered during the machining process. The subsequent correction cycle realizes mounting and metrology references down to sub-micron precision using diamond-machining techniques. This approach facilitates the assembly of demanding optical systems and even freeform arrangements in a predictable and passive manner. Different machining setups as well as the corresponding metrology approaches are demonstrated, and results are presented for representative components. The effectiveness of the approach is discussed using rotationally symmetrical lens systems and a snap-together freeform mirror system.

scholarly journals Intelligent Optical Systems Using Adaptive Optics

2012 ◽  
Vol 82 ◽  
pp. 64-74
Author(s):  
Natalie Clark
Keyword(s):  
Adaptive Optics ◽  
Situational Awareness ◽  
Focal Length ◽  
Optical Design ◽  
Optical Systems ◽  
Deformable Mirrors ◽  
Spatial Light Modulators ◽  
Active Components ◽  
Light Modulators ◽  
Commercial Applications

Until recently, the phrase adaptive optics generally conjured images of large deformable mirrors being integrated into telescopes to compensate for atmospheric turbulence. However, the development of smaller, cheaper devices has sparked interest for other aerospace and commercial applications. Variable focal length lenses, liquid crystal spatial light modulators, tunable filters, phase compensators, polarization compensation, and deformable mirrors are becoming increasingly useful for other imaging applications included guidance navigation and control (GNC), coronagraphs, foveated imaging, situational awareness, autonomous rendezvous and docking, non-mechanical zoom, phase diversity, and enhanced multi-spectral imaging. Active components presented allow flexibility in the optical design, increasing performance. In addition, the intelligent optical systems presented offer advantages in size and weight and radiation tolerance.

Multilayer Polymer Films for Photonic Applications

2009 ◽  
Vol 1196 ◽  
Author(s):  
Juefei Zhou ◽  
Kenneth Singer ◽  
Hyunmin Song ◽  
Yeheng Wu ◽  
Joseph Lott ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Low Cost ◽  
Optical Systems ◽  
Laser Dyes ◽  
Active Components ◽  
Polymeric Systems ◽  
Roll To Roll ◽  
Laser Systems ◽  
One Step ◽  
Tunable Refractive Index

AbstractPolymers are receiving considerable attention as components in novel optical systems because of the tailored functionality, easy manufacturing, and relatively low cost. The processing of layered polymeric systems by coextrusion is a method to produce films comprising hundreds to thousands of alternating layers with thickness spanning the nanoscale to microscale in a single, one-step roll-to-roll process. Several layered polymer optical systems have been fabricated by coextrusion, including tunable refractive index elastomers, photonic crystals, and mechanically tunable photonic crystals. Layered polymeric optical systems made by coextrusion can also incorporate active components such as laser dyes for all-polymer laser systems.

Atomic Resolution in Crystal Aperture Stem

1990 ◽  
Vol 48 (1) ◽  
pp. 236-237
Author(s):  
J T Fourie
Keyword(s):  
Optical System ◽  
Spherical Aberration ◽  
Three Dimensional ◽  
Transmission Function ◽  
Optical Systems ◽  
Bragg Angle ◽  
Electron Optical System ◽  
Intimate Contact ◽  
Diffraction Effects ◽  
Design Aspect

The attempts at improvement of electron optical systems to date, have largely been directed towards the design aspect of magnetic lenses and towards the establishment of ideal lens combinations. In the present work the emphasis has been placed on the utilization of a unique three-dimensional crystal objective aperture within a standard electron optical system with the aim to reduce the spherical aberration without introducing diffraction effects. A brief summary of this work together with a description of results obtained recently, will be given.The concept of utilizing a crystal as aperture in an electron optical system was introduced by Fourie who employed a {111} crystal foil as a collector aperture, by mounting the sample directly on top of the foil and in intimate contact with the foil. In the present work the sample was mounted on the bottom of the foil so that the crystal would function as an objective or probe forming aperture. The transmission function of such a crystal aperture depends on the thickness, t, and the orientation of the foil. The expression for calculating the transmission function was derived by Hashimoto, Howie and Whelan on the basis of the electron equivalent of the Borrmann anomalous absorption effect in crystals. In Fig. 1 the functions for a g220 diffraction vector and t = 0.53 and 1.0 μm are shown. Here n= Θ‒ΘB, where Θ is the angle between the incident ray and the (hkl) planes, and ΘB is the Bragg angle.

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