摘要:

Strained quantum‐well lasers emitting at 4.5 &mgr;m have been fabricated. The laser structure, grown on a GaSb substrate by molecular beam epitaxy, consists of compressively strained InAsSb active layers and tensile‐strained InAlAs barrier layers, surrounded by AlAsSb cladding layers. Under electrical injection, the laser exhibited pulsed operation up to 85 K, with threshold current density of 350 A/cm2at 50 K. Under optical pumping, the laser operated pulsed up to 144 K, with peak power at 95 K of 0.54 W. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.113810

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The dependence of the eigenstates of a high‐finesse Fabry–Pe´rot cavity on intracavity circular phase anisotropies is shown to provide a very sensitive method to measure small Faraday rotations. The method is experimentally checked by measuring the Verdet constant of the air and a sensitivity of 10−10rad is reported. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113811

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Efficient pulsed room‐temperature laser operation at 946 nm has been achieved by end‐pumping Nd:YAG with multiple diode array bars. High average power operation was made possible by the use of a water‐cooled composite doped/undoped Nd:YAG laser rod. A 5.7 W output at 946 nm was obtained at 500 Hz in long‐pulsed operation. Over 15% efficiency based on incident pump power was measured at 300 Hz. With intracavity frequency doubling using KNbO3, 366 mW was obtained at 473 nm and 200 Hz.

ISSN:0003-6951    

DOI:10.1063/1.113812

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We present ultrahigh precision measurements of the optical heterogeneity of high quality fused silica at the &dgr;n=10−8index level. The measurements were made with a unique scanning heterodyne interferometer developed as part of the Gravity Probe‐B Program. Striae of refractive index variation &Dgr;n<10−7(optical path difference smaller than 5 nm) are clearly visible on an extended heterogeneity background of around &Dgr;n=6×10−7. Both striae and extended heterogeneities are repeatable to within a few parts in 108. These results show the nature and extent of the heterogeneities of high quality vitreous silica. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113813

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A diffraction grating in silicon with 50 nm lines and spaces is illuminated with diffraction‐born evanescent waves from its transparent replica. A rotation &fgr; between the gratings results in a set of fringes with period &lgr;fthat is larger than the period of the original gratings by a magnification factorM. These fringes are induced and observed with a photon tunneling microscope having an incident illumination of 650 nm in air. This super‐resolution by what may be considered a form of optical heterodyning with evanescent waves is discussed. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113814

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We describe the use of flared waveguide diode lasers for obtaining increased output power under mode‐locked operation. The flared waveguide expands the optical mode from a narrow region which gives a single lateral optical mode, to a wider multimode region for higher pulse saturation energy. Flared gain and flared absorber section geometry devices are compared to devices with conventional uniform waveguides. Using flared gain section devices, improvements in both pulse energy (6.8 pJ) and pulsewidth (3.3 ps) were measured compared to uniform waveguide devices. Peak powers of over 2 W are obtained, which, to our knowledge, is the highest peak power obtained directly from mode‐locked single stripe diode lasers. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113786

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

By performing interferometric measurements on the fundamental transverse mode of a planar VCSEL, we have determined the wave front curvature inside the VCSEL cavity. The results show that the (apparent) position of the beam waist is 0–8 &mgr;m below the surface of the top DBR, i.e., up to 25% of the Rayleigh range. From these results we estimate the amount of index and gain guiding in the VCSEL. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113787

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We report on an erbium cascade laser in a fluorozirconate fiber. Lasing on the transition4I11/2→4I13/2at 2.71 &mgr;m is supported by colasing on the transition4S3/2→4I9/2at 1.72 &mgr;m. This recycles the excitation that is lost via excited‐state absorption and avoids the saturation of the output power. Threshold at 2.71 &mgr;m is 33 mW launched pump power at 791 nm. The measured slope efficiency of 22.6% is relatively close to the 29.1% stokes‐efficiency limit. An output power of 158 mW is obtained, limited only by the 1.43 W power available from the Ti: sapphire pump laser. Output power is 15 and slope efficiency 2.5 times higher than reported in previous publications. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113788

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

New types of focusing optical devices based on glass‐capillary converters (GCCs) for the extreme ultraviolet (EUV) region have been constructed and tested. The EUV spectra of He II (np‐1s) line radiation have been recorded in the spectral region from 23.0 to 30.6 nm both with and without GCC. Experimentally an enhancement of EUV radiation by a factor of 4–5 has been demonstrated for a small solid angle of the detection system. Theoretically, a computer simulation has been performed producing an enhancement coefficient of about 30–50 for optimal conditions of such experiments. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113789

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The temperature dependence of refractive indices (dn/dT) for crystalline and amorphous silicon is analyzed critically by use of a recently introduced physically meaningful model to find refractive indices at any operating temperature and wavelength. The opposite sign of the measured thermo‐optic coefficients of the amorphous silicon at 0.6328 and 0.752 &mgr;m is investigated and is explained as due to the inverted position of the isentropic band gap rather than the crystalline silicon. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113790

出版商:AIP    

年代:1995

数据来源: AIP