Understanding beam alignment in a coherent lidar system

Narasimha S. Prasad; Chandrasekhar Roychoudhuri,

doi:10.1117/12.2025460

1 October 2013 Understanding beam alignment in a coherent lidar system

Narasimha S. Prasad, Chandrasekhar Roychoudhuri,

Proceedings Volume 8832, The Nature of Light: What are Photons? V; 88320A (2013) https://doi.org/10.1117/12.2025460
Event: SPIE Optical Engineering + Applications, 2013, San Diego, California, United States

Abstract

Optical beam alignment in a coherent lidar (or ladar) receiver system plays a critical role in optimizing its performance. Optical alignment in a coherent lidar system dictates the wavefront curvature (phase front) and Poynting vector) matching of the local oscillator beam with the incoming receiver beam on a detector. However, this alignment is often not easy to achieve and is rarely perfect. Furthermore, optical fibers are being increasingly used in coherent lidar system receivers for transporting radiation to achieve architectural elegance. Single mode fibers also require stringent mode matching for efficient light coupling. The detector response characteristics vary with the misalignment of the two pointing vectors. Misalignment can lead to increase in DC current. Also, a lens in front of the detector may exasperate phase front and Poynting vector mismatch. Non-Interaction of Waves, or the NIW property indicates the light beams do not interfere by themselves in the absence of detecting dipoles. In this paper, we will analyze the extent of misalignment on the detector specifications using pointing vectors of mixing beams in light of the NIW property.

Citation Download Citation

Narasimha S. Prasad and Chandrasekhar Roychoudhuri, "Understanding beam alignment in a coherent lidar system", Proc. SPIE 8832, The Nature of Light: What are Photons? V, 88320A (1 October 2013); https://doi.org/10.1117/12.2025460

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available