Optical Lumped Element MKIDs Ben Mazin, February 2012 The Optical/UV MKID Team: UCSB: Ben Mazin, Sean McHugh, Kieran O’Brien, Seth Meeker, Erik Langman, Danica Marsden, Matt Strader Caltech: Jonas Zmuidzinas, Sunil Golwala, David Moore JPL: Bruce Bumble, Rick LeDuc Mazin UCSB

Microwave Kinetic Inductance Detectors Cooper Pair Energy Gap Silicon – eV Aluminum – eV Energy resolution: Inductor is a Superconductor! MKID Equivalent Circuit Typical Single Photon Event

SCI2-B: Demonstrated at Palomar! Mazin et al., Optics Express 2012

Tapering Uniform Legs Rectangular Legs Trapezoidal Legs

3500x Over or under etch of up to 100 nm, but leg widths consistent to 25 nm

SCI2-B Energy Resolution 20 nm TiN on Silicon Tc = 0.8 K QP lifetime ~ 50 μ s Q i ~ 1,000,000 R=E/ Δ E=16 at 254 nm R limited by HEMT/power handling/Q i

SCI-2B Uniformity

Lessons Learned and Outstanding Questions First MKID device with multiple feedlines (I think?) Must have good ground planes or massive crosstalk Floating finite CPW not OK! T c gradients cause resonator collisions – simulate your frequency coding scheme with gradients to avoid systematic collision issues QP lifetime varies substantially, even on a single device microsecond spread! Strange! Need more robust algorithms for setting up large arrays Choosing resonators Figuring out optimal powers

ARCONS Overview Array Camera for Optical to Near-IR Spectrophotometery (ARCONS) First Light: July 28, 2011, Palomar 200” Coudé Lens coupled 1024 (32x32) pixel array in cryogen-free ADR (first lens coupled optical/nIR 100 mK instrument – learned a lot about IR blocking!) 0.2” pixels yields 7”x7” FOV Next run, 45x45 pixels with 0.4” plate scale yields 18”x18” FOV 400 nm to 1100 nm simultaneous bandwidth with maximum count rate of ~2000 cts/pixel/sec Next run, nm Energy resolution R~10-20 at 400 nm 50 Gbit/sec -> FPGA -> 32 Mbit/sec Entrance window

Optics 300K 3K (Lyot Stop) 100 mK IR Blocking 300K 4K 4K Dewar Lyot Reimaging Window Stop Optics See Kieran O’Brien for Details

Readout Crate Sean McHugh’s Talk Tomorrow

To Palomar!

ARCONS ft 5.67 ft 135 ft

ARCONS First Light Image

Crab Pulsar Archival pulse profile for Crab (Shearer 2003) Pulse profile measured with ARCONS

Dancing with the Stars

Mega-z Proposed Keck Nasmyth Instrument (dewar doesn’t tip past ~50 degrees, flexure concerns) Uses an aperture mask in the focal plane to image objects of interest only Maps one object to one MKID pixel Sky subtraction done with empty Macropixels Active mask alignment using feedback from science array 10’x10’ or 12’ diameter FOV. 10,000 objects. R~50 m I < – 1.35 μm (possibly up to 1.8 μm) 6”x6” Macropixels (image not to scale)

Simulated Mega-Z Spectra

Future Plans Field ARCONS in fall (Lick) and winter (Palomar) with a 2025 pixel array Detector Goals (Danica’s Talk): Eliminate substrate events (already done?) Increase energy resolution Increase uniformity Increase QE