Heterodyne performance and characteristics of terahertz MgB₂hot electron bolometers

We have studied THz heterodyne detection in sub-micrometer MgB2 hot electron bolometer (HEB) mixers based on superconducting MgB2 films of ∼ 5 nm (HEB-A), corresponding to a critical temperature (Tc) of 33.9 K, and ∼ 7 nm (HEB-B), corresponding to a T c of 38.4 K. We have measured a double sideband (DSB) receiver noise temperature of 2590 K...

Beam Waist Properties of Spiral Antenna Coupled HEB Mixers at Supra-THz Frequencies

We have simulated and measured the beam properties of lens-antenna coupled hot electron bolometer mixers at a few supra-terahertz frequencies between 1.4 and 5.3 THz. The quasi-optical structures consist of an elliptical lens and a logarithmic spiral antenna. The model used for our simulations consists of a finite-element analysis to simulate...

5.3 THz MgB2 hot electron bolometer mixer operated at 20 K

Heterodyne receivers combining a NbN HEB mixer with a local oscillator (LO) are the work horse for high resolution (≥106) spectroscopic observations at supra-terahertz frequencies. We report an MgB2 HEB mixer working at 5.3 THz with<br/>20 K operation temperature based on a previously published paper [Y. Gan et al, Appl. Phys. Lett., 119, 202601...

Gal/Xgal U/LDB Spectroscopic/Stratospheric THz Observatory:: GUSTO

Gal/Xgal U/LDB Spectroscopic/ Stratospheric THz Observatory (GUSTO) is a NASA Explorers Mission of Opportunity that will make large scale maps of the Milky Way and Large Magellanic Cloud in three important interstellar lines: [CII], [OI], and [NII] at 158, 63, and 205 μm, respectively. During its ~75 day stratospheric (~36 km) flight, GUSTO’s 0...

8-beam local oscillators multiplexer for GUSTO at 4.7 THz

We will report a full demonstration of the Fourier phase grating used as 4.7 THz local oscillator (LO) multiplexer for Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO). The design, modeling, tolerance analysis, and experimental characterization of the angular and intensity distributions among 2 × 4 output beams and the...

Bandwidth of a 4.7 THz beam multiplexer based on Fourier grating

We present an analysis of the bandwidth of an asymmetric 8-beam Fourier grating as the beam multiplexer for a 4.7 THz local oscillator used in a heterodyne receiver. We take the grating designed for NASA GUSTO balloon observatory as an example to address the bandwidth question although it does not need to operate over a wide frequency range....

4.7 THz asymmetric beam multiplexer for GUSTO

A full demonstration of the Fourier phase grating used as 4.7 THz local oscillator (LO) multiplexer for Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO) is presented in this paper, including its design, modeling, tolerance analysis, and experimental characterizations of the angular and intensity distributions among 2 ×...

3.9 THz spatial filter based on a back-to-back Si-lens system

We present a terahertz spatial filter consisting of two back-to-back (B2B) mounted elliptical silicon lenses and an opening aperture defined on a thin gold layer between the lenses. The beam filtering efficiency of the B2B lens system is investigated by simulation and experiment. Using a unidirectional antenna coupled 3rd-order distributed...

81 supra-THz beams generated by a Fourier grating and a quantum cascade laser

Large heterodyne receiver arrays (~100 pixel) allow astronomical instrumentations to map more area within limited space mission lifetime. One challenge is to generate multiple local oscillator (LO) beams. Here, we succeeded in generating 81 beams at 3.86 THz by combining a reflective, metallic Fourier grating with an unidirectional antenna...

Wideband on-chip terahertz spectrometer based on a superconducting filterbank

Terahertz spectrometers with a wide instantaneous frequency coverage for passive remote sensing are enormously attractive for many terahertz applications, such as astronomy, atmospheric science, and security. Here we demonstrate a wide-band terahertz spectrometer based on a single superconducting chip. The chip consists of an antenna coupled...

Quantum cascade lasers as super terahertz local oscillators for astronomy

Quantum cascade laser (QCL) technology has made a breakthrough in THz radiation sources, opening a new window into variety of applications. QCLs are compact, low-consumption and narrow linewidth lasers with relatively high output powers, capable to emit radiation across the whole super-THz (2-6 THz) range. These are all demanded for spectroscopy...

8-beam local oscillator array at 4.7 THz generated by a phase grating and a quantum cascade laser

We present an 8-beam local oscillator (LO) for the astronomically significant [OI] line at 4.7 THz. The beams are generated using a quantum cascade laser (QCL) in combination with a Fourier phase grating. The grating is fully characterized using a third order distributed feedback (DFB) QCL with a single mode emission at 4.7 THz as the input....

Efficiency of multi-beam Fourier phase gratings at 1.4 THz

We compare the results of simulated and measured power efficiency and far-field beam pattern, for two reflective Fourier phase gratings, designed to generate 2 x 2 and 2 x 4 beams respectively from a single-beam, coherent source at 1.4 THz. The designed surface structures were manufactured on aluminum plates by a computer numerical control ...

A 4.7 THz HEB QCL receiver for STO2

We report on a 4.7 THz heterodyne receiver designed for high resolution spectroscopy of the astronomically important neutral oxygen (OI) line at 4.745 THz. The receiver is based around a hot electron bolometer (HEB) mixer and quantum cascade laser (QCL) local oscillator. This receiver has been developed to fly on the Stratospheric Terahertz...

Simultaneous frequency locking and monitoring using a bi-directional THz quantum cascade laser

We have performed frequency locking of a dual, forward reverse emitting 3rd order distributed feedback quantum cascade laser (QCL) at 3.5 THz. By using both directions of THz emission in combination with two gas cells and two power detectors, we can for the first time perform frequency stabilization, while monitor the frequency locking...

Frequency Locking and Monitoring Based on Bi-directional Terahertz Radiation of a 3rd-Order Distributed Feedback Quantum Cascade Laser

We have performed frequency locking of a dual, forward reverse emitting third-order distributed feedback quantum cascade laser (QCL) at 3.5 THz. By using both directions of THz emission in combination with two gas cells and two power detectors, we can for the first time perform frequency stabilization, while monitor the frequency locking quality...