Audio communications with a mid-IR laser

Kenneth J. Grant; Bradley A. Clare; Wayne Martinsen; Miro Dubovinsky; William Isterling; Daniel Wright; Kerry A. Mudge

doi:10.1117/12.803579

2 October 2008 Audio communications with a mid-IR laser

Kenneth J. Grant, Bradley A. Clare, Wayne Martinsen, Miro Dubovinsky, William Isterling, Daniel Wright, Kerry A. Mudge

Proceedings Volume 7115, Technologies for Optical Countermeasures V; 71150I (2008) https://doi.org/10.1117/12.803579
Event: SPIE Security + Defence, 2008, Cardiff, Wales, United Kingdom

Abstract

We have demonstrated audio communications with a mid-IR laser. The laser is a frequency doubled Q-switched CO₂ system producing approximately 12ns pulses at 4.6μm. The audio signal was encoded on the beam by means of pulse frequency modulation (PFM) with a carrier frequency of 37kHz. A 1mm diameter, low noise thermoelectrically cooled IR photovoltaic detector with electrical bandwidth 250MHz was used to detect the laser beam. A custom-built circuit stretched the resultant electrical pulses to approximately 1.5μs, before being demodulated. High quality audio signals were received and recorded, and still images were successfully transmitted using slow scan television techniques. The demonstration was conducted at the Defence Science & Technology Organisation's laser range at Edinburgh, South Australia in July 2008. The distance was 1.5km, with a slant path (8m to 1.5m). The maximum range using this system is estimated to be tens of kilometres.

Citation Download Citation

Kenneth J. Grant, Bradley A. Clare, Wayne Martinsen, Miro Dubovinsky, William Isterling, Daniel Wright, and Kerry A. Mudge "Audio communications with a mid-IR laser", Proc. SPIE 7115, Technologies for Optical Countermeasures V, 71150I (2 October 2008); https://doi.org/10.1117/12.803579

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