scholarly journals Speckle Reduction Techniques in Semiconductor Lasers

2014 ◽  
Vol 42 (7) ◽  
pp. 551
Author(s):  
Hiroshi MURATA ◽  
Yasuyuki OKAMURA ◽  
Kazuhisa YAMAMOTO
Keyword(s):  
Semiconductor Lasers ◽  
Speckle Reduction ◽  
Reduction Techniques

Laser speckle reduction techniques for mid-infrared microscopy and stand-off spectroscopy

2017 ◽  
Author(s):  
Robert Furstenberg ◽  
Christopher A. Kendziora ◽  
Christopher J. Breshike ◽  
Viet Nguyen ◽  
R. Andrew McGill
Keyword(s):  
Laser Speckle ◽  
Speckle Reduction ◽  
Infrared Microscopy ◽  
Mid Infrared ◽  
Reduction Techniques

Speckle Noise Diffusion in Knee Articular Cartilage Ultrasound Images

2020 ◽  
Vol 16 (6) ◽  
pp. 739-751
Author(s):  
Muhammad Ali Shoaib ◽  
Md Belayet Hossain ◽  
Yan Chai Hum ◽  
Joon Huang Chuah ◽  
Maheza Irna Mohd Salim ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Contrast Ratio ◽  
Speckle Noise ◽  
Absolute Error ◽  
Cartilage Injury ◽  
Speckle Reduction ◽  
Ultrasound Images ◽  
Low Contrast ◽  
Reduction Techniques ◽  
Articular Cartilage Injury

Background: Ultrasound (US) imaging can be a convenient and reliable substitute for magnetic resonance imaging in the investigation or screening of articular cartilage injury. However, US images suffer from two main impediments, i.e., low contrast ratio and presence of speckle noise. Aims: A variation of anisotropic diffusion is proposed that can reduce speckle noise without compromising the image quality of the edges and other important details. Methods: For this technique, four gradient thresholds were adopted instead of one. A new diffusivity function that preserves the edge of the resultant image is also proposed. To automatically terminate the iterative procedures, the Mean Absolute Error as its stopping criterion was implemented. Results: Numerical results obtained by simulations unanimously indicate that the proposed method outperforms conventional speckle reduction techniques. Nevertheless, this preliminary study has been conducted based on a small number of asymptomatic subjects. Conclusion: Future work must investigate the feasibility of this method in a large cohort and its clinical validity through testing subjects with a symptomatic cartilage injury.

Speckle reduction techniques in medical ultrasound imaging

2014 ◽  
Vol 4 (1) ◽  
pp. 32-40 ◽  
Author(s):  
Jihoon Park ◽  
Jin Bum Kang ◽  
Jin Ho Chang ◽  
Yangmo Yoo
Keyword(s):  
Ultrasound Imaging ◽  
Speckle Reduction ◽  
Medical Ultrasound ◽  
Medical Ultrasound Imaging ◽  
Reduction Techniques

APPLICATIONS OF QUANTUM DOTS IN SEMICONDUCTOR LASERS

2002 ◽  
Vol 12 (01) ◽  
pp. 177-205 ◽  
Author(s):  
Nikolai N. Ledentsov ◽  
Victor M. Ustinov ◽  
Dieter Bimberg ◽  
James A. Lott ◽  
Zh. I. Alferov
Keyword(s):  
Quantum Dots ◽  
Semiconductor Lasers ◽  
Continuous Wave ◽  
Single Mode ◽  
Cavity Surface ◽  
Defect Reduction ◽  
Reduction Techniques ◽  
Self Organized ◽  
Vertical Cavity Surface ◽  
Emitting Lasers

Quantum Dots (QD) provide unique opportunities to extend all the basic properties of heterostructure lasers and move further their applications. Practical fabrication of QD lasers became possible when techniques for self-organized growth allowed fabrication of dense and uniform arrays of narrow-gap nanodomains, coherently inserted in a semiconductor crystal matrix. Using of InAs QD lasers enabled significant improvement of device performance and extension of the spectral range on GaAs substrates to mainstream telecom wavelengths. Continuous wave 1.3 μm room-temperature output power of ~300 mW single mode for edge-emitters and of 1.2 mW multimode for vertical-cavity surface-emitting lasers are realized. Long operation lifetimes are manifested. The breakthrough become possible both due to development of self-organized growth and defect-reduction techniques in QD technology.

Sign in / Sign up

Export Citation Format

Share Document