current progress in the scaling of continuous wave optical output power and conversion efficiency of broad-area GaAs-based edge emitters, broad-area lasers (BALs), operating in the 900 & mldr;1000 nm wavelength ra...
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current progress in the scaling of continuous wave optical output power and conversion efficiency of broad-area GaAs-based edge emitters, broad-area lasers (BALs), operating in the 900 & mldr;1000 nm wavelength range is presented. Device research and engineering efforts have ensured that BALs remain the most efficient of all light sources, so that in the past 10 years, power conversion efficiency at 20 W continuous wave (CW) output power from BA lasers with a 90 & mldr;100 mu m wide stripe has increased 1.5-fold to 57% (via epitaxial layer designdevelopments), whilst peak CW power per single emitter has increased around 3-fold to 70 W (via scaling of device size), with further scaling underway, for example via use of multi-junction designs. However, the peak achievable CW power conversion efficiency and CW specific output power (defined here as peak output power from a 100 mu m stripe diode lasers with a single p-n junction) has changed remarkably little, remaining around 70% and 25 W, respectively, for the past decade. Fortunately, research to understand the limits to peak efficiency and specific output power has also shown progress. Specifically, recent studies indicate that spatial non-uniformity in optical field and temperature play a major role in limiting both power and conversion efficiency. Technological efforts motivated by these discoveries to flatten lateral and longitudinal temperature profiles have successfully increased both power and efficiency. In addition, epitaxial layer designs with very high modal gain successfully reduce threshold current and increase slope at 25 degrees C to values comparable to those observed at 200 K, offering a path toward the 80% conversion efficiency range currently seen only at these cryogenic temperatures. Overall, whilst operating efficiency and power continue to scale rapidly, a technological path for increased specific power and peak efficiency is also emerging.
Lightsails are a highly promising spacecraft concept that has attracted interest in recent years due to its potential to travel at near-relativistic speeds. Such speeds, which current conventional crafts cannot reach,...
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An analysis of the measuring accuracy that can be obtained using critical angle refractometry as a direct and an indirect method is made. The working conditions required to get the highest accuracy are discussed.
ISBN:
(纸本)0819406554
An analysis of the measuring accuracy that can be obtained using critical angle refractometry as a direct and an indirect method is made. The working conditions required to get the highest accuracy are discussed.
Mathematical expressions are presented to relate object and image plane tilts in nonaxially symmetric systems. Examples that illustrate the use of these expressions are given. Keystone distortion is described and quan...
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ISBN:
(纸本)0819406554
Mathematical expressions are presented to relate object and image plane tilts in nonaxially symmetric systems. Examples that illustrate the use of these expressions are given. Keystone distortion is described and quantified as a function of image plane tilt.
Geometric parameters such as fill-factor, pixel shape, and array symmetry strongly affect the performance of membrane light modulators. A set of modeling tools that allow device performance evaluation as a function of...
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ISBN:
(纸本)0819406554
Geometric parameters such as fill-factor, pixel shape, and array symmetry strongly affect the performance of membrane light modulators. A set of modeling tools that allow device performance evaluation as a function of these parameters have been developed. The models predict the effect of varying a given parameter and allow visualization of the result. The current modeling results are in good agreement with experimental observation and have formed the basis for computer-aided design of future generations of such devices.
The expressions of the Seidel aberration theory are comparatively simple and easy to use due to its characteristics and prerequisites. Meanwhile, the effective range of the theory is limited also due to its prerequisi...
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ISBN:
(纸本)0819406554
The expressions of the Seidel aberration theory are comparatively simple and easy to use due to its characteristics and prerequisites. Meanwhile, the effective range of the theory is limited also due to its prerequisites. The possibility for enlarging its effective range is analyzed in this paper.
We have developed zoom lens design expert system intended to operate with little user intervention. The paper puts the emphasis on the knowledge representation, system architecture, reasoning and control strategy of t...
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Electronic speckle pattern interferometry (ESPI) is a wholefield non-contact optical metrology technique for displacement measurement, based on the optical physics of surface-generated laser speckle. Since its incepti...
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Electronic speckle pattern interferometry (ESPI) is a wholefield non-contact optical metrology technique for displacement measurement, based on the optical physics of surface-generated laser speckle. Since its inception during the early 1970s ESPI has gradually evolved into different opticaldesigns and has been applied to a range of engineering and non-engineering applications. Development of ESPI has continued during the 1990s with the introduction of new laser and optical technology into the interferometers, allowing further optimization and extending the potential applicability of the technique. This review considers the most notable developments of interferometer design and application that have occurred and been widely published during the 1990s, and examines the current and near-future direction of research into the technique.
The revisions of enlarging all the aberrations related to aperture to the seventh order for the Seidel aberration theory have been proposed in this paper. The practice of the revised theory in the range of small viewi...
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ISBN:
(纸本)0819406554
The revisions of enlarging all the aberrations related to aperture to the seventh order for the Seidel aberration theory have been proposed in this paper. The practice of the revised theory in the range of small viewing field and large aperture (for example, the lens of microscope and telescope) has proven that the theory is applicable in this scale.
A method of investigation of the optical properties of anisotropic materials using modulation of tho light polarization is presented. Measuring set-up was constructed and used to examine tho optical properties of inte...
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