' Neshyba 



Q = 0. 8 Ma\ 



M ^ ' 



where M = mediari energy flux over the band, taken as 

 7x10" ^w/cm^ (equation 13), 

 A\ = 80 %band-width of the luminescent spectra, i.e. 

 lOOmfj.. 

 These typical values yield a spectral irradiance of 5. 6 x 10" micro- 

 ■watts/cm^/millimicron. Accounting for the 10% transmittance of the 

 filter reduces spectral irradiance to 5. 6 x lO""""^. For the one milli- 

 micron filter pass band, this also becomes the bioluminescent energy 

 flux background in the filtered receiver, and is plotted as point o' on 

 curve (b) of Figure 2. 



One concludes that for the filter-modified receiver, range 

 performance is limited by receiver noise rather than by the lumi- 

 nescent background. However, due to the loss in the inserted filter, 

 no additional gain in range has been achieved. 



Summary 



It is shown that the stimulated bioluminescent field can be 

 the factor that limits the maximum useful mapping range of an 

 underwater lidar. This limitation can be circumvented only at the 

 expense of sophistication in the system design, namely, the incor- 

 poration of a low-loss, narrow pass-band optical filter. Finally, 

 it should be stated that the field of stimulated bioluminescence will 

 not be everywhere the same; extensive measurements of the field 

 near the ocean bottom have not been reported. 



References 



Neshyba, S, 1967. In Situ Stimulation of Marine Bioluminescence by 

 Pulsed Light, Limnology and Oceanography, in press. 



Flint, G. W. 1964. Analysis and Optimization of Laser Ranging 



Techniques, lEE Trans, on Mil. Elect, , Vol. MIL-8, Jan. 

 1964. 



Povejsil, D. J. , Roven, R. S., and Waterman, P. I96I. Airborne 

 Radar, D. Van Nostrand Co. , New York, 823 pp, 



Clarke, G.L. , and Hubbard, C.J. 1959. Quantitative Records of the 

 Luminescent Flashing of Oceanic Animals at Great Depths. 

 Limn. & Ocean, , Vol, 4. 



Clarke, G. L. , and Denton, E. J. 1962. Light and Animal Life, 

 The Sea, Vol, I, Interscience, New York, 1962. 



438 



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