Chao Chang

US Patent:

20130294465, Nov 7, 2013

Filed:

May 3, 2013

Appl. No.:

13/887009

Inventors:

Chao Chang - San Jose CA, US
Laurence E. Cramer - Mountain View CA, US

International Classification:

H01S 3/108

US Classification:

372 10, 372 22

Abstract:

The specification and drawings present an apparatus and a method for intra-cavity harmonic generation in lasers such as solid-state lasers using a multi-resonance cavity with meniscus lenses for focusing corresponding wavelength radiation components on non-linear optical elements such as non-linear optical crystals using type I or type II phase-matching for significantly increasing efficiency of the harmonic conversion and output powers of generated harmonics. Using only type I or only type II phase-matching for all non-linear crystals may eliminate the requirement of linear-polarization on the fundamental laser wavelength generation. For example, a highly efficient UV Nd:YAG laser at 355 nm (a third harmonic of the fundamental wavelength of 1064 nm for the Nd:YAG laser) using intra-cavity triple resonance cavity and meniscus lenses has been developed using embodiments described herein.

US Patent:

20210063329, Mar 4, 2021

Filed:

Aug 26, 2019

Appl. No.:

16/551616

Inventors:

- Milpitas CA, US
Chao Chang - San Jose CA, US

International Classification:

G01N 23/2206
G01N 23/2204
G01N 23/207
H01L 21/66

Abstract:

Methods and systems for measuring structural and material characteristics of semiconductor structures based on wavelength resolved, soft x-ray reflectometry (WR-SXR) at multiple diffraction orders are presented. WR-SXR measurements are simultaneous, high throughput measurements over multiple diffraction orders with broad spectral width. The availability of wavelength resolved signal information at each of the multiple diffraction orders improves measurement accuracy and throughput. Each non-zero diffraction order includes multiple measurement points, each different measurement point associated with a different wavelength. In some embodiments, WR-SXR measurements are performed with x-ray radiation energy in a range of 10-5,000 electron volts at grazing angles of incidence in a range of 1-45 degrees. In some embodiments, the illumination beam is controlled to have relatively high divergence in one direction and relatively low divergence in a second direction, orthogonal to the first direction. In some embodiments, multiple detectors are employed, each detecting different diffraction orders.