?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Mechanically+robust+cylindrical+metal+terahertz+waveguides+for+cryogenic+applications&rft.creator=Wallis%2C+R&rft.creator=Degl'Innocenti%2C+R&rft.creator=Mitrofanov%2C+O&rft.creator=Waldie%2C+J&rft.creator=Bledt%2C+CM&rft.creator=Melzer%2C+JE&rft.creator=Harrington%2C+JA&rft.creator=Beere%2C+HE&rft.creator=Ritchie%2C+DA&rft.description=As+the+ambition+behind+THz+quantum+cascade+laser+based+applications+continues+to+grow%2C+abandoning+free-space+optics+in+favor+of+waveguided+systems+promises+major+improvements+in+targeted%2C+easy+to+align%2C+and+robust+radiation+delivery.+This+is+especially+true+in+cryogenic+environments%2C+where+illumination+is+traditionally+challenging.+Although+the+field+of+THz+waveguides+is+rapidly+developing%2C+most+designs+have+limitations+in+terms+of+mechanical+stability+at+low+temperatures%2C+and+are+costly+and+complicated+to+fabricate+to+lengths+%3E+1+m.+In+this+work%2C+we+investigate+readily+available+cylindrical+metal+waveguides+which+are+suitable+for+effective+power+delivery+in+cryogenic+environments%2C+and+explore+the+optimal+dimensions+and+materials+available.+The+materials+chosen+were+extruded+un-annealed+and+annealed+copper%2C+as+well+as+stainless+steel%2C+with+bore+diameters+of+1.75%2C+2.5%2C+and+4.6+mm.+Measurements+were+performed+at+three+different+frequencies%2C+2.0%2C+2.85+and+3.2+THz%2C+with+optimal+transmission+losses+%3C3+dB%2Fm+demonstrated+at+2.0+THz.+Additionally%2C+novel+optical+couplers+are+also+presented+and+characterised%2C+with+the+ability+to+change+the+beam+path+by+90%C2%B0+with+a+coupling+loss+of+just+2.2+dB+whilst+maintaining+mode+quality%2C+or+thermally+isolate+sections+of+waveguide+with+a+coupling+loss+as+low+as+0.5+dB.+The+work+presented+here+builds+on+previous+work1%2C+and+forms+a+comprehensive+investigation+of+cryogenically+compatible+THz+waveguides+and+optical+couplers%2C+paving+the+way+for+a+new+generation+of+systems+to+utilize+THz+QCLs+for+a+host+of+low-temperature+investigations.&rft.subject=Science+%26+Technology%2C+Technology%2C+Physical+Sciences%2C+Engineering%2C+Electrical+%26+Electronic%2C+Optics%2C+Physics%2C+Applied%2C+Engineering%2C+Physics%2C+Terahertz+waveguides%2C+quantum+cascade+laser%2C+mode+profile%2C+beam+shaping%2C+cryogenics%2C+optical+components%2C+QUANTUM+CASCADE+LASERS%2C+TRANSMISSION%2C+RADIATION&rft.publisher=SPIE+-+International+Society+of+Optical+Engineering&rft.contributor=Sadwick%2C+LP&rft.contributor=Yang%2C+T&rft.date=2017-01-30&rft.type=Proceedings+paper&rft.publisher=Conference+on+Terahertz%2C+RF%2C+Millimeter%2C+and+Submillimeter-Wave+Technology+and+Applications+X&rft.language=eng&rft.source=+++++In%3A+Sadwick%2C+LP+and+Yang%2C+T%2C+(eds.)++(Proceedings)+Conference+on+Terahertz%2C+RF%2C+Millimeter%2C+and+Submillimeter-Wave+Technology+and+Applications+X.+(pp.+p.+1010307).++SPIE+-+International+Society+of+Optical+Engineering+(2017)+++++&rft.format=text&rft.identifier=https%3A%2F%2Fdiscovery.ucl.ac.uk%2Fid%2Feprint%2F1573059%2F1%2FMitrofanov_Mechanically%2520robust%2520cylindrical%2520metal%2520terahertz%2520waveguides%2520for%2520cryogenic%2520applications.pdf&rft.identifier=https%3A%2F%2Fdiscovery.ucl.ac.uk%2Fid%2Feprint%2F1573059%2F&rft.rights=open