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 StraderCaltech: Jonas Zmuidzinas, Sunil Golwala, David MooreJPL: Bruce Bumble, Rick LeDuc

Mazin Lab @ UCSB

Microwave Kinetic Inductance Detectors

Cooper Pair

Energy GapSilicon – 1.10000 eVAluminum – 0.00018 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

Measured @ 3500xMeasured @ 3500x

22.22.42.62.833.23.43.63.84

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Site

Wid

th (u

m)

B-0207

B-0210

B-0310

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 μs

Qi ~ 1,000,000

R=E/ΔE=16 at 254 nm

R limited by HEMT/power handling/Qi

SCI-2B Uniformity

Lessons Learned and Outstanding Questions

First MKID device with multiple feedlines (I think?)

Must have good ground planes or massive crosstalkFloating finite CPW not OK!

Tc 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. 20-100 microsecond spread! Strange!

Need more robust algorithms for setting up large arrays

Choosing resonatorsFiguring out optimal powers

ARCONS OverviewArray 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” FOVNext 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, 350-1350 nm

Energy resolution R~10-20 at 400 nm

50 Gbit/sec -> FPGA -> 32 Mbit/sec

Entrancewindow

Optics

300K 3K (Lyot Stop) 100 mK

IR Blocking

300K 4K 4KDewar Lyot ReimagingWindow Stop Optics

See Kieran O’Brien for Details

Readout Crate

Sean McHugh’s Talk Tomorrow

To Palomar!

ARCONS

16.67 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-zProposed 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 pixelSky subtraction done with empty MacropixelsActive mask alignment using feedback from science array

10’x10’ or 12’ diameter FOV. 10,000 objects.

R~50

mI < 26

0.32 – 1.35 μm (possibly up to 1.8 μm)

6”x6” Macropixels (image not to scale)

Simulated Mega-Z Spectra

Future PlansField ARCONS in fall (Lick) and winter (Palomar) with a 2025 pixel array

Detector Goals (Danica’s Talk):Eliminate substrate events (already done?)Increase energy resolutionIncrease uniformityIncrease QE