Roger S Allen

US Patent:

40126919, Mar 15, 1977

Filed:

Apr 8, 1976

Appl. No.:

5/674999

Inventors:

Filbert J. Bartoli - Upper Marlboro MD
Leon Esterowitz - Springfield VA
Roger E. Allen - Alexandria VA
Melvin R. Kruer - Oxon Hill MD

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01R 2702

US Classification:

324 65R

Abstract:

A method of determining thermal constants of bonding layers of an infrared ensor which comprises cooling a bonded layer sensor to 77. degree. K and then heating the sensor by a quick pulse of heat. The electrical resistance of the sensor is measured and the measurement continued to determine a thermal profile. The measured thermal profile is compared with a known profile to determine thickness of the bonding layers and the material layers.

US Patent:

41173295, Sep 26, 1978

Filed:

Apr 22, 1977

Appl. No.:

5/790130

Inventors:

Melvin R. Kruer - Oxon Hill MD
Leon Esterowitz - Springfield VA
Filbert J. Bartoli - Upper Marlboro MD
Roger E. Allen - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01J 100
G01T 122

US Classification:

250338

Abstract:

A photoconductive detector comprising a thin film of photoconductive material deposited on a thin substrate of high thermal conductivity having a surface area that is large relative to the detector's absorbing surface area. The back surface of the substrate is metalized and soldered to a high-thermal-conductivity, large-thermal-mass heat buffer which is coupled to a heat sink. The resulting detector is hardened against damage resulting from laser irradiation.

US Patent:

42175470, Aug 12, 1980

Filed:

Feb 13, 1979

Appl. No.:

6/011821

Inventors:

Filbert J. Bartoli - Upper Marlboro MD
Leon Esterowitz - Springfield VA
Roger E. Allen - Alexandria VA
Melvin R. Kruer - Oxon Hill MD

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01R 3126
G01R 2702

US Classification:

324158R

Abstract:

A method for determining the compensation density of narrow-gap semiconductors. Photo-excited carriers are generated by uniformily irradiating a sample with a laser pulse of a particular density and pulse width for a particular time length and at a low sample temperature. The laser wavelength is chosen with a photon energy sufficiently high that carriers are excited from the conduction band by normal intrinsic absorption (one-photon absorption). Subsequent to the laser pulse, conductivity-voltage measurements are taken as a function of time during the photo-electron decay. Such measurements are made for different applied source-detector connections on the same sample with identical pulse-time values for each different correction. The sample is then laser-pulsed as before with a magnetic field normal to the sample surface to obtain Hall-voltage measurements. The measurements are averaged for the same time duration and the average of all curves are used in the determination.

US Patent:

50383531, Aug 6, 1991

Filed:

Feb 21, 1990

Appl. No.:

7/488411

Inventors:

Leon Esterowitz - Springfield VA
Roger E. Allen - Alexandria VA
Gregory J. Kintz - Mountain View CA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H01S 316

US Classification:

372 41

Abstract:

A laser system employing thulium and holmium in a trivalent state. The quantum levels of interest in the thulium and holmium are coupled so that one pumping photo absorbed by the thulium results in two photons emitted by the holmium, making for an unusually efficient laser system. The lower level is sufficiently depopulated at room temperature to allow laser operation without cryogenics. In preferred embodiments, the laser pump can be a laser diode, itself especially efficient, and whose output frequency is closely matched in photon energy to the thulium quantum state of interest, thus lending additional efficiency to the overall system. The thulium and the holmium exist in an yttrium-aluminum garnet crystal as lattice replacements for yttrium.

US Patent:

53134770, May 17, 1994

Filed:

Oct 30, 1992

Appl. No.:

7/968890

Inventors:

Leon Esterowitz - Springfield VA
Roger E. Allen - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H01S 307
H01S 3094

US Classification:

372 6

Abstract:

A continuous wave(CW) activator ion doped fiber laser is presented which lases at a normally self-terminating laser transition at a slope efficiency greater than that achieved by a self-terminating fiber laser. Two laser transitions, one corresponding to a self-terminating laser transition and the other to a transition out of the lower level of the self-terminating transition, are simultaneously stimulated in the activator ion doped fiber. Through simultaneous lasing of the two wavelengths corresponding to these transitions, the lower level of the self-terminating transition is sufficiently depopulated so that CW operation is achieved.

US Patent:

43474853, Aug 31, 1982

Filed:

May 23, 1979

Appl. No.:

6/041969

Inventors:

Leon Esterowitz - Annandale VA
Roger E. Allen - Alexandria VA
Melvin R. Kruer - Oxon Hill MD
Filbert J. Bartoli - Upper Marlboro MD

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H01S 314

US Classification:

372 42

Abstract:

A method of achieving inversion in solid-state rare-earth materials for blue-green laser operation. A XeF excimer laser is used to pump a matching transition in divalent ytterbium in a host material. The host material is co-doped with a trivalent ion such as praseodymium (Pr. sup. 3+) so that energy transfer to the trivalent ion will take place. Laser action is then from the Pr. sup. 3+ ion. Alternative matching absorption transitions also occur in the trivalent rare-earth ions of Tb, Dy, Ho, and Nd.

US Patent:

49674161, Oct 30, 1990

Filed:

Feb 28, 1990

Appl. No.:

7/486638

Inventors:

Leon Esterowitz - Springfield VA
Roger E. Allen - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H01S 330

US Classification:

372 6

Abstract:

A room temperature laser system for producing a CW laser emission at substially 2. 3 microns is disclosed. In a preferred embodiment, the laser system comprises a laser diode source for producing a CW pump beam at a preselected wavelength; and a fiber laser doped with thulium activator ions sufficient to produce an output CW laser emission at a wavelength in the range of 2. 2-2. 5 microns when the fiber laser is pumped by the CW pump beam.

US Patent:

50848801, Jan 28, 1992

Filed:

Jul 2, 1990

Appl. No.:

7/546818

Inventors:

Leon Esterowitz - Springfield VA
Roger E. Allen - Alexandria VA

Assignee:

The United States of America as represented by the Sectretary of the Navy - Washington DC

International Classification:

H01S 317

US Classification:

372 6

Abstract:

A room temperature laser system for producing a CW Laser emission at substantially 2. 7 microns is disclosed. In a preferred embodiment, the laser system comprises a laser diode source for producing a CW pump beam at a preselected wavelength; and a fiber laser doped with erbium activator ions to produce an output CW laser emission at a wavelength in the range of 2. 71-2. 78 microns when the fiber laser is pumped by the CW pump beam.