Selective Spectral Detection Of Continuum Terahertz Radiation

The knowledge of THz continuum spectra is essential to investigate the emission mechanisms by high energy particle acceleration processes. Technical challenges appear for obtaining selective spectral sensing in the far infrared range to diagnose radiation produced by solar flare burst emissions measured from space as well as radiation produced by high energy electrons in laboratory accelerators. Efforts are been carried out intended for the development of solar flare high cadence radiometers at two THz frequencies to operate outside the terrestrial atmosphere (i.e. at 3 and 7 THz). One essential requirement is the efficient suppression of radiation in the visible and near infrared. Experimental setups have been assembled for testing (a) THz transmission of "low-pass" filters: rough surface mirrors; membranes Zitex G110G and TydexBlack; (b) a fabricated 2.4 THz resonant grid band-pass filter transmission response for polarization and angle of incidence; (c) radiation response from distinct detectors: adapted commercial microbolometer array using HRFZ-Si window, pyroelectric module and Golay cell; qualitative detection of solar radiation at a sub-THz frequency has been tested with a microbolometer array placed at the focus of the 1.5 m reflector for submillimeter waves (SST) at El Leoncito, Argentina Andes. © 2010 SPIE.7741Harris, D.C., (1999) Materials for Infrared Windows and Domes, , SPIE Optical Engineering Press, Washington, USASiegel, P.H., THz technology: An overview (2003) International Journal of High Speed Electronics and Systems, 13 (2), pp. 1-44Mlynczak, M., Johnson, D., Bingham, G., Far-Infrared Spectroscopy of the Troposphere (FIRST) project (2003) Proceedings of Geoscience and Remote Sensing Symposium, 1, p. 512Sherwin, M.S., Schmuttenmaer, C.A., Bucksbaum, P.H., (2004) Proceedings of DOE-NSF-NIH Workshop on Opportunities in THz Science, , Arlington, VAKinch, M.A., (2007) Infrared Detector Materials, , SPIE Optical Engineering Press, TT76, Washington, USA, DCStrabala, K.I., Ackerman, S.A., Menzel, W.P., Cloud Properties inferred from 8-12-μm Data (1994) Journal of Applied Meteorology, 33 (2), p. 212Williams, G.P., FAR-IR/THz radiation from the Jefferson Laboratory, energy recovered linac, free electron laser (2002) Rev. Sci. Instrum., 73, pp. 1461-1463Kaufmann, P., Raulin, J.-P., Can microbunch instability on solar flare accelerated electron beams account for bright broadband coherent synchrotron microwaves? (2006) Phys. Plasmas, 13. , 070701-070701-4Klopf, J.M., (2008) 1st SMESE Workshop, , 10-12 March, Paris, FranceKaufmann, P., (2004) Astrophys. J., 603, pp. L121Kaufmann, P., Continuum terahertz radiation detection using membrane filters (2009) International Microwave and Optoelectronics Conference, SBMO & IEEE-MTT, pp. 262-266. , Nov. 3-6 2009, Belem, Para, BrazilBennett, H.E., Porteus, J.O., Relation between surface roughness and specular reflectance at normal incidence (1961) J. Opt. Soc.Am., 51, pp. 123-129Kostiuk, T., Deming, D., A solar infrared photometer for space flight application (1991) Infrared Physics, 32, pp. 225-233Romberg, M., Rough mirrors for the thz frequency range (2008) Proc. MOMAG 2008 - 13th SBMO and 8th CBMAG, pp. 365-367. , Florianópolis, SC, Brazil, 7-10 September 2008Benford, D.J., Gaidis, M.C., Kooi, J.W., Optical properties of Zitex in the infrared to submillimeter (2003) Applied Optics, 42, pp. 5118-5122(2008), www.tydex.ru, Tydex JSCo, St. Petersburg, Russia, Technical Note on THz materials and componentsKaufmann, P., Flare infrared experiment (FIRE) (1998) NASA Proposal to FBMS in Response to AO-98-OSS-01Melo, A.M., Metal mesh resonant filters for terahertz frequencies (2008) Applied Optics, 47, pp. 6064-6069MacDonald, M.E., Spectral transmittance of lossy printed resonant-grid terahertz bandpass filters (2000) IEEE Trans. on Microwave Theory and Techniques, 48, pp. 712-718http://www.ino.ca/en-CAKaufmann, P., New telescopes for ground-based solar observations at submillimeter and mid-infrared (2008) Proc. SPIE, 7012. , Ground-based and airborne telescopes II (ed. By L.M. Stepp and R. Gimozzi), 70120L-1-70120L-8(2008), ESSCO, West Concord, MA, USA, private communicationhttp://www.spectrumdetector.comhttp://www.tydexoptics.com/productsl/thz-optics/golay-cell