摘要:

Experimental verification is made of a new polarization splitter which utilizes artificial anisotropic dielectrics. The splitter is composed of layers of periodically laminated SiO2/TiO2thin films. The SiO2and TiO2films are alternately deposited by rf sputtering and reactive dc sputtering, respectively. The thickness of each layer is 50 nm, while the total number of the layers amounts to 2000. The measured polarization split angles are 5.7° (&lgr;=0.63 &mgr;m) and 5.1° (&lgr;=1.3 &mgr;m), being roughly the same as those predicted.

ISSN:0003-6951    

DOI:10.1063/1.104691

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report the performance of a type‐I lithium triborate (LBO) optical parametric amplifier pumped by 15 ps, 355 nm laser pulses. It is seen that with proper design, LBO can be as efficient as barium borate for such an application.

ISSN:0003-6951    

DOI:10.1063/1.104692

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Tunable, flashlamp‐pumped laser properties are discribed for the crystal Cr:LiSrAlF6(Cr:LiSAF) in both long pulse andQ‐switched modes of operation. Slope efficiencies of 5%, overall efficiency of 3%, and a tuning range from 780 to 1010 nm are reported.

ISSN:0003-6951    

DOI:10.1063/1.104693

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Optical amplifiers with strained‐layer multiple quantum well active regions are shown to exhibit a bandwidth of 100 nm with a saturation output power larger than 25 mW. For a 780‐&mgr;m‐long device, the small‐signal gain exceeds 25 dB. The combination of high gain with large saturation output power is obtained by properly tailoring the mode confinement factor and differential gain coefficient of the strained‐layer gain medium.

ISSN:0003-6951    

DOI:10.1063/1.104694

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We have demonstrated a new method of generating pulses of freely propagating THz electromagnetic radiation. The resulting 380 fs pulses are the shortest directly measured THz pulses in free space to date and are more powerful than those generated by Hertzian dipoles or by resonant dipole antennas. Temporal features as short as 190 fs were observed on these THz radiation pulses and thereby, illustrate an ultrafast receiver response time.

ISSN:0003-6951    

DOI:10.1063/1.104695

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Using polyimide as host in a guest‐host thin film we demonstrate the first poled‐polymer electro‐optic response stable at temperatures up to 150 °C (samples poled and cured at 250 °C). A coplanar‐electrode poling geometry is used so that the molecular alignment of the guest dye between the electrodes is coincident with the free volume of the host. We hypothesize that ‘‘high’’ temperature poling during the imidization process, when the polyimide forms rings and densifies, accounts for the excellent poled response stability.

ISSN:0003-6951    

DOI:10.1063/1.104696

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We have fabricated InGaAs/AlGaAs strained‐layer distributed‐feedback grating‐surface‐emitting lasers with a buried grating structure. The device consists of a pumped distributed‐feedback section terminated on both sides by unpumped distributed Bragg reflector sections. cw operation in a stable single longitudinal mode is achieved up to six times threshold. The threshold current density is ∼600 A/cm2. The far‐field beam divergence is predominantly single lobed and diffraction limited. The spectral linewidth is 1.0 MHz at an output power of 8 mW.

ISSN:0003-6951    

DOI:10.1063/1.104697

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Noncollinear difference frequency mixing is reported for the first time in a barium borate crystal that generates near‐infrared radiation tunable from 2.04 to 3.42 &mgr;m. The technique apart from verifying a very simple relation correlating the phase‐matching angle with the noncollinear angle of the interacting beams provides a simple alternative scheme for generating coherent radiation in this important spectral range.

ISSN:0003-6951    

DOI:10.1063/1.104698

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

By comparison of the measuredKfactors (ratio of the damping factor to the square of the resonance frequency) of distributed feedback and Fabry–Perot lasers, it is found that the relaxation time associated with nonlinear gain for 1.3 &mgr;m InGaAsP lasers is about 0.1 ps. This short time constant is consistent with spectral hole burning being the dominant process responsible for the nonlinear gain.

ISSN:0003-6951    

DOI:10.1063/1.104699

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Spatially resolved electric field measurements in the cathode region of a dc glow discharge in hydrogen are performed using polarization‐dependent Stark broadening of plasma‐induced emission of the Balmer lines. The large concentrations of excited atoms in the sheath provide an accurate, sensitive measure of discharge electric fields.

ISSN:0003-6951    

DOI:10.1063/1.104700

出版商:AIP    

年代:1991

数据来源: AIP