摘要:

We report the first observation of large‐freguency‐shift (2000 to over 4000 cm−1) phase‐matched stimulated four‐photon mixing in low‐mode‐number silica fibers and discuss the use of this process for efficient frequency conversion in the visible, the near IR, and the near UV region of the spectrum.

ISSN:0003-6951    

DOI:10.1063/1.92424

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A novel optical device based on a ’’dynamical refractive‐index change’’ in an amorphous As2S3film is constructed. In this device coupling of a red light beam into the thin‐film waveguide with a prism coupler is controlled by illuminating blue light. A switching time of about 10 s and an on/off ratio as high as 6/1 have been achieved. Further, this device can be operated as a photo‐optical switch having a storage function by changing the intensity of the light beams.

ISSN:0003-6951    

DOI:10.1063/1.92425

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Embedded single and multimode waveguides on fused quartz substrates have been fabricated by high‐speed silica deposition and accurate reactive sputter etching by a C2F6gas plasma. These waveguides have rectangular cross sections with an aspect ratio close to unity. Total waveguide loss was approximately 5 dB/cm, and absorption loss measured by laser calorimetry at 637‐nm wavelength was less than 0.1 dB/cm.

ISSN:0003-6951    

DOI:10.1063/1.92426

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Photothermal radiometry (PTR) is shown to yield optical absorption spectra in the visible region of untreated and strongly scattering material, using Nd2O3powder, blood, and a green leaf as test samples. A conventional high pressure Xe lamp/monochromator combination was employed for illumination at power levels below 1 mW, with a PbSnTe infrared detector for recording the thermal reradiation. Calculated PTR signals and signal‐to‐noise ratios are found to compare well with those observed.

ISSN:0003-6951    

DOI:10.1063/1.92427

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The optical gain and transient absorption spectra for the IF 490‐nm and ICl 430‐nm bands have been measured in discharge‐excited He, CF3I and NF3or CCl4gas mixtures using a flashlamp–‐pumped, tunable dye laser. For the IF blue‐green band, gain in excess of 1.0% cm−1was observed over the entire 479–498‐nm wavelength interval. Peak optical gain coefficients of ∼3.0% cm−1and 1.3% cm−1were observed for IF at 490.7 nm and ICl at 431.3 nm, respectively. For both molecules, strong absorption in the vicinity of the wavelength of maximum gain was identified as being due to the He (2p1P1) excited species. The addition of Ne or Ar to the gas mixture was found to substantially reduce the He (1P1) density, thereby improving the IF small‐signal gain‐to‐absorption ratio as well as the temporal width of the gain pulse.

ISSN:0003-6951    

DOI:10.1063/1.92428

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Through intracavity degenerate four‐wave interaction the reflectivity of the phase‐conjugated signal is shown to exhibit bistability and hysteresis when the driving pump field is varied in a continuous matter. The nonlinear medium inside the Fabry‐Perot cavity may be in one‐ or two‐photon resonance with the pump. We suggest suitable materials and discuss possible applications of the bistable response of the reflectivity.

ISSN:0003-6951    

DOI:10.1063/1.92429

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

We originally propose and demonstrate optical parallel logic operations such as level slicing and the NOT and Exclusive OR (EXOR) operations using emission‐pulse time delay in a fiber laser plate and gating technique. These operations are essential for the optical digitial computations.

ISSN:0003-6951    

DOI:10.1063/1.92430

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

It is demonstrated by model calculations and experimental results, that the range of viewing angles of a twisted nematic (TN) display can be considerably improved by using a liquid‐crystal material with a low refractive index anisotropy Dn<0.1.

ISSN:0003-6951    

DOI:10.1063/1.92421

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The time‐resolved optical transmission of silicon has been observed at l = 1.15 mm during irradiation by an 8‐nsec pulsed laser at 485 nm with several energy densities in the range of 0.25 to 1.2 J/cm2. The transmission exhibits a sudden brief drop consistent with the rise and fall of the reflectivity enhancement. However, the transmission does not exhibit the strong absorption expected of molten silicon with a skin depth of ∼100 A˚.

ISSN:0003-6951    

DOI:10.1063/1.92422

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Proton‐bombarded stripe‐geometry (12×380 mm) lasers have been fabricated from multiquantum‐well (MQW) heterostructure wafers grown by molecular beam epitaxy (MBE). cw current thresholds as low as 76 mA were obtained in spite of the reduced optical confinement factor G in these lasers. Such values are comparable with the lowest values obtained from similar stripe‐geometry proton‐bombarded double‐heterostructure (DH) lasers. There also appears to be an improvement in the linearity and ’’tracking’’ of the output powers from the end mirrors in these MQW lasers over DH lasers using the same proton‐irradiated stripe‐geometry for current injection. Such improvements are results of a better lateral mode stabilization with injection currents. Significant beam width reduction in the direction perpendicular to the junction plane was obtained. The half‐power full‐width q⊥as narrow as 25° was obtained. For the stripe‐geometry lasers fabricated from some MQW wafers, the characteristic temperatureT0in the current threshold‐temperature dependence can be as high as 293 °C in the temperature range of 10–70 °C.

ISSN:0003-6951    

DOI:10.1063/1.92423

出版商:AIP    

年代:1981

数据来源: AIP