A 4.7THz heterodyne receiver for a balloon borne telescope

We report on the performance of a high sensitivity 4.7 THz heterodyne receiver based on a NbN hot electron bolometer mixer and a quantum cascade laser (QCL) as local oscillator. The receiver is developed to observe the astronomically important neutral atomic oxygen [OI] line at 4.7448 THz on a balloon based telescope. The single-line frequency control and improved beam pattern of QCL have taken advantage of a third-order distributed feedback structure. We measured a double sideband receiver noise temperature (Trec(DSB)) of 815 K, which is ~ 7 times the quantum noise limit (hν/2kB). An Allan time of 15 s at an effective noise fluctuation bandwidth of 18 MHz is demonstrated. Heterodyne performance was further supported by a measured methanol line spectrum around 4.7 THz.

[1]  Qing Hu,et al.  Perfectly phase-matched third-order distributed feedback terahertz quantum-cascade lasers. , 2012, Optics letters.

[2]  A. Davies,et al.  Terahertz semiconductor-heterostructure lasers , 2002, Summaries of Papers Presented at the Lasers and Electro-Optics. CLEO '02. Technical Diges.

[3]  T. M. Klapwijk,et al.  Terahertz heterodyne spectrometer using a quantum cascade laser , 2010 .

[4]  H. Müller,et al.  Submillimeter, millimeter, and microwave spectral line catalog. , 1985, Applied optics.

[5]  Mattias Beck,et al.  Low divergence Terahertz photonic-wire laser. , 2010, Optics express.

[6]  Yuan Ren,et al.  Hot electron bolometer heterodyne receiver with a 4.7-THz quantum cascade laser as a local oscillator , 2012, 1208.5776.

[7]  B. Krauskopf,et al.  Proc of SPIE , 2003 .

[8]  David A. Ritchie,et al.  Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line , 2010 .

[9]  B. Williams.  Terahertz quantum cascade lasers , 2007, 2008 Asia Optical Fiber Communication & Optoelectronic Exposition & Conference.

[10]  Qing Hu,et al.  Terahertz tomography using quantum-cascade lasers. , 2012, Optics letters.

[11]  D. J. Hayton,et al.  Stabilized hot electron bolometer heterodyne receiver at 2.5 THz , 2012 .

[12]  T. Klapwijk,et al.  Noise temperature and beam pattern of an NbN hot electron bolometer mixer at 5.25 THz , 2010 .

[13]  Brian J. Drouin,et al.  Torsion–rotation global analysis of the first three torsional states (νt = 0, 1, 2) and terahertz database for methanol , 2008 .

[14]  Erick T. Young,et al.  The Stratospheric TeraHertz Observatory (STO) , 2008 .

[15]  Qing Hu,et al.  Frequency locking of single-mode 3.5-THz quantum cascade lasers using a gas cell , 2012 .