Erik Shirokoff
Introduction
Erik Shirokoff

I'm currently a postdoctoral scholar at the California Institute of Technology. My work includes the study of the Cosmic Mcrowave Background (CMB) and the high-redshift universe, though my principal focus is instrumentation and the development of sensitive cryogenic detectors for mm and submm-wavelength astronomy. I spend most of my time on two projects: the South Pole Telescope, a dedicated 10-meter telescope and TES bolometer array which maps the CMB at small angular scales, and SuperSpec, an on-chip, mm-wavelength, filter-bank spectrometer based on MKIDs.

Today, the South Pole Telescope is leading the field in observations of the CMB temperature power spectrum at small angular scales and the discovery of galaxy clusters through the Sunyaev-Zel'dovich (SZ) effect. The first instrument deployed at the SPT, the SZ camera, consists of a 960 element array of horn-coupled TES bolometers which observe the sky in three atmospheric frequency windows at 90, 150, and 220 GHz, read out using Superconducting Quantum Interference Devices (SQUIDs) and frequency domain multiplexing. In December of 2012, the SZ camera successfully completed the observation of 2500 square degtrees of the southern sky. This survey enables several complimentary science goals, including the discovery of hundreds of galaxy clusters at a range of redshifts using the the Sunyaev-Zel'dovich (SZ) effect, and the statistical detection of SZ power from unresolved sources in the resulting power spectrum. In addition to providing a wealth of information on cluster physics, foregrounds, and rare point sources, these data (when combined with optical followup) can significantly constrain the dark energy equation of state, the large scale matter power spectrum (σ8), and the duration and character of reionization. In 2012, a new polarization-sensitive receiver was deployed at SPT, which will extend the SPT science program to include the search for CMB B-mode polarization.

SuperSpec is a novel, ultra-compact spectrograph-on-a-chip for millimeter and submillimeter wavelength astronomy. Its very small size, wide spectral bandwidth, and highly multiplexed detector readout will enable construction of powerful multibeam spectrometers for high-redshift observations. SuperSpec employs a filter bank consisting of planar, lithographed superconducting transmission line resonators. Each mm-wave resonator is weakly coupled to both the feedline and to the inductive portion of a lumped element Microwave Kinetic Inductance Detector (MKID). Incoming mm-wave radiation breaks Cooper pairs in the MKID, modifying its kinetic inductance and resonant frequency, allowing for frequency-multiplexed readout. The design is realized using thin film lithographic structures on a Si wafer, with titanium nitride MKID resonators. We're currently working on the development of a demonstration instrument which will consist of two 500-channel, R=700 spectrometers, one operating in the 1-mm atmospheric window and the other covering the 650 and 850 micron bands. Eventually we expect the same technology to enable a kilopixel spectrometer for the CCAT telescope.

If you happen to be a student here at Caltech and are interested in learning more about SuperSpec, don't hestitate to get in touch with me. There will be a lot of exciting opportunities to get involved in both the hardware and the astronomy aspects of the project in coming years.


I am a member of the Zmuidzinas submm group in the Caltech Astronomy Department and am afiliated with the Physics, Math, and Astronomy division and the The Keck Institute for Space Studies.