摘要:

A beta barium borate (&bgr;‐BaB2O4or BBO) crystal has been used to electro‐opticallyQswitch both diode‐pumped and lamp‐pumped Nd:YLF laser systems, resulting in stable, high average power operation. Piezoelectric ringing was found to have negligible effects on the performance of the BBO Pockels cell at repetition rates up to 6 kHz. The high damage threshold and low insertion loss of BBO permitted operation up to average powers in excess of 6 kW/cm2, which makes a BBO Pockels cell well suited for high power, small mode volume operation, such as in diode‐pumped solid state lasers. Based on typical diode‐pumped laser parameters, BBO is expected to extend simple compactQ‐switched operation of diode‐pumped lasers to average powers of 30–100 W. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113675

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We show ultra‐low‐threshold lasing due to morphology‐dependent resonances from an europium (Eu)‐chelate‐doped microdroplet with ∼90 &mgr;m diameter. Spectra and spatial images between lasing and nonlasing are exhibited with comparison. Temporal responses are discussed from the viewpoint of the faster (direct) and slower (indirect) transitions in Eu chelates. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.113857

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A procedure to improve the sensitivity of thetwo‐colorZ‐scantechniqueis presented. The sensitivity of the technique as a function of the pump and the probe beam confocal parameters and their relative transverse dimensions is evaluated. The results show that, in the case of small nonlinear phase shift, the sensitivity of the measurements at the probe beam center may be a factor of 4 greater by the appropriate choice of the beams parameters. Results for arbitrary phase shift values and for detection at or out of the probe beam center are also reported. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113858

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We describe the operation and performance of a dual fiber optical trap created using tapered lensed optical fibers pigtailed to 1300 nm laser diodes. Single‐mode fibers, having mode field diameters of ∼9.5 &mgr;m, and separated by up to 350 &mgr;m, are used to demonstrate dielectric particle confinement over two orders of magnitude in fiber trapping power ratio. Axial and transverse trap efficiencies, as well as the existence of bistable trapping positions, are predicted and experimentally confirmed. The use of fiber lenses results in the creation of an optical trap that provides strong transverse optical confinement and which is nearly insensitive to the fiber polarization state. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113859

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Two different types of irradiation systems based on dodecahedral configuration are proposed for 60, 72, 80, and 92 beams. By optimizing the system, it is expected that enough uniformity (≤1% rms) is provided. Furthermore, it is quantitatively discussed that the number of beams, power imbalance, and the beam pattern must be improved synchronously for a high illumination uniformity. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113860

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The dependence on the source location of photothermal bistabilities of a thin CdS:Cu film is demonstrated by the investigation of bistability in luminescence in reflection geometry. Particularly, it is shown that the infrared portion in the reflected beam clearly exhibits contrasting bistable loops in contrast to the reflection itself. The unexpected effect is explained by the fact that bistability in luminescence is a bulk feature which is not affected by the surface region. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113861

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Degenerate four‐wave mixing in alkali vapors exhibits a strong dependence on the angle between the forward pump and probe beams, due to atomic motion. We show that this angular dependence is dramatically decreased by including several hundred Torr of N2buffer gas in a potassium vapor cell. The angle at which the signal has decreased by half is 250 mrad, an improvement of over 50 times the angle for potassium vapor without buffer gases. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113862

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Gain coefficient of excitonic transitions is calculated for unstrained as well as strained ZnCdSe/ZnMgSSe multiple quantum well (MQW) lasers as a function of operating wavelength and injection current. Unlike the III–V strained layer quantum well lasers, the gain coefficient due to excitonic transitions is significantly higher in II–VI systems as the exciton binding energy is more than 5 times larger. This results in a primary role for excitons in lasing which has been verified experimentally. Strain induced changes in energy band gaps and effective masses of light and heavy holes are included in the gain and threshold current density calculations, which are in agreement with experimental data available for compressive strained layers grown on GaAs substrates. Significantly low threshold current density of about 180 A/cm2are predicted for the tensile strained ZnCdSe–ZnMgSSe and ZnCdSe–ZnSeTe quantum well lasers using InP substrates. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113863

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We investigate the transient emission of two In0.2Ga0.8As/GaAs microcavity laser samples with one and three quantum wells at 20 K following femtosecond optical excitation. The stimulated emission time is faster when the cavity resonance is tuned to shorter wavelengths within the gain spectrum of the quantum well. A larger number of quantum wells makes the dynamical response faster also. The narrowest pulse width observed is 6.8 ps, and the shortest rise time is 1 ps. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.113864

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Pulse operation of electron cyclotron resonance plasma was performed for the fabrication of diamond films by chemical vapor deposition. With square wave amplitude modulation of microwaves at 500 Hz in frequency, the growth rate became twice as large as one of continuous operation with the same microwave power. Time resolved measurement of the optical emission from the pulse modulated plasma was also carried out. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113865

出版商:AIP    

年代:1995

数据来源: AIP