ABSTRACT. We present the design, construction, and commissioning results of ARCONS, the Array Camera for Optical to Near-IR Spectrophotometry. ARCONS is the first ground-based instrument in the optical through near-IR wavelength range based on microwave kinetic inductance detectors (MKIDs). MKIDs are revolutionary cryogenic detectors, capable of detecting single photons and measuring their energy without filters or gratings, similar to an X-ray microcalorimeter. MKIDs are nearly ideal, noiseless photon detectors, as they do not suffer from read noise or dark current and have nearly perfect cosmic ray rejection. ARCONS is an integral field spectrograph (IFS) containing a lens-coupled 2024 pixel MKID array yielding a 20″ × 20″ field of view and has been deployed on the Palomar 200 inch and Lick 120 inch telescopes for 24 nights of observing. We present initial results showing that ARCONS and its MKID arrays are now a fully operational and powerful tool for astronomical observations.

Abstract:Microwave Kinetic Inductance Detectors, or MKIDs, have proven to be a powerful cryogenic detector technology due to their sensitivity and the ease with which they can be multiplexed into large arrays. A MKID is an energy sensor based on a photon-variable superconducting inductance in a lithographed microresonator, and is capable of functioning as a photon detector across the electromagnetic spectrum as well as a particle detector. Here we describe the first successful effort to create a photon-counting, energy-resolving ultraviolet, optical, and near infrared MKID focal plane array. These new Optical Lumped Element (OLE) MKID arrays have significant advantages over semiconductor detectors like charge coupled devices (CCDs). They can count individual photons with essentially no false counts and determine the energy and arrival time of every photon with good quantum efficiency. Their physical pixel size and maximum count rate is well matched with large telescopes. These capabilities enable powerful new astrophysical instruments usable from the ground and space. MKIDs could eventually supplant semiconductor detectors for most astronomical instrumentation, and will be useful for other disciplines such as quantum optics and biological imaging.

Design and analysis of multi-color confocal microscopy with a wavelength scanning detector Rev. Sci. Instrum. 83, 053704 (2012) Short wavelength thermography: Theoretical and experimental estimation of the optimal working wavelength J. Appl. Phys. 111, 084903 (2012) Hole shape effect induced optical response to permittivity change in palladium sub-wavelength hole arrays upon hydrogen exposure J. Appl. Phys. 111, 084502 (2012) Few-photon-level two-dimensional infrared imaging by coincidence frequency upconversion Appl. Phys. Lett. 100, 151102 (2012) Channelling optics for high quality imaging of sensory hair Rev. Sci. Instrum. 83, 045001 (2012) Additional information on Rev. Sci. Instrum. Microwave kinetic inductance detectors (MKIDs) are superconducting detectors capable of counting single photons and measuring their energy in the UV, optical, and near-IR. MKIDs feature intrinsic frequency domain multiplexing (FDM) at microwave frequencies, allowing the construction and readout of large arrays. Due to the microwave FDM, MKIDs do not require the complex cryogenic multiplexing electronics used for similar detectors, such as transition edge sensors, but instead transfer this complexity to room temperature electronics where they present a formidable signal processing challenge. In this paper, we describe the first successful effort to build a readout for a photon counting optical/near-IR astronomical instrument, the ARray Camera for Optical to Nearinfrared Spectrophotometry. This readout is based on open source hardware developed by the Collaboration for Astronomy Signal Processing and Electronics Research. Designed principally for radio telescope backends, it is flexible enough to be used for a variety of signal processing applications.

We demonstrate single-photon counting at 1550 nm with titanium-nitride (TiN) microwave kinetic inductance detectors. Energy resolution of 0.4 eV and arrival-time resolution of 1.2 microseconds are achieved. 0-, 1-, 2-photon events are resolved and shown to follow Poisson statistics. We find that the temperature-dependent frequency shift deviates from the Mattis-Bardeen theory, and the dissipation response shows a shorter decay time than the frequency response at low temperatures. We suggest that the observed anomalous electrodynamics may be related to quasiparticle traps or subgap states in the disordered TiN films. Finally, the electron density-of-states is derived from the pulse response.Fast and efficient photon-counting detectors at nearinfrared wavelengths are in high demand for advanced quantum-optics applications such as quantum key distribution[1] and linear-optics quantum computing [2]. Superconducting detectors, including superconducting nanowire detectors [3] and transition-edge sensors (TES) [4], show great promise in these applications. For example, TES made from tungsten films have shown over 95 % of quantum efficiency and photon-number resolving power at 1550 nm [5]. On the other hand, microwave kinetic inductance detectors (MKIDs) have quickly developed into another major superconducting detector technology for astronomical instruments from submillimeter to x-ray [6,7]. The main advantages of MKIDs are that they are simple to fabricate and easy to multiplex into a large detector array. Recently, the AR-CRON camera[8], a MKID array made from titanium nitride (TiN) films developed for UV/Optical/NIR imaging and spectroscopy [9], has been successfully demonstrated at the Palomar 200-inch telescope. These TiN MKIDs have already shown good photon-counting and energyresolving capability, but so far they have been considered only for astronomy applications. In this letter, we describe a single-photon-counting experiment at 1550 nm with TiN MKIDs and discuss their promise for application in quantum optics. Another motivation for the work in this letter is to use these detectors to study the electrodynamics and microwave properties of TiN, which is a relatively new material for MKIDs. Anomalous electrodynamics of TiN is discussed and the density of states * U.S. government work not protected by U.S. copyright. N 0 = 3.9 × 10 10 eV −1 µm −3 is derived. MKIDs are thin-film, high-Q superconducting microresonators whose resonance frequency f r and internal quality factor Q i (or internal dissipation) change when incoming radiation with photon energy above twice the gap energy (hν > 2∆) breaks Cooper pairs in the superconductor [6]. The measurements of frequency shift and internal dissipation signals are referred to as frequency readout and dissipation readout, respectively. The principle of operation of the MKID, as well as the readout schemes, were explained in detail in a recent review paper [10].A recent breakthrough in MKID development is the application of titanium nitride (TiN), a new material for super...

We present DARKNESS (the DARK-speckle Near-infrared Energy-resolving Superconducting Spectrophotometer), the first of several planned integral field spectrographs to use optical/near-infrared Microwave Kinetic Inductance Detectors (MKIDs) for high-contrast imaging. The photon counting and simultaneous low-resolution spectroscopy provided by MKIDs will enable real-time speckle control techniques and post-processing speckle suppression at framerates capable of resolving the atmospheric speckles that currently limit high-contrast imaging from the ground. DARKNESS is now operational behind the PALM-3000 extreme adaptive optics system and the Stellar Double Coronagraph at Palomar Observatory. Here we describe the motivation, design, and characterization of the instrument, early on-sky results, and future prospects.