### Abstract

Kinetic Inductance Detectors (KIDs) provide a promising solution to the problem of producing large format arrays of ultra sensitive detectors for astronomy. Traditionally KIDs have been constructed from superconducting quarter-wave resonant elements capacitively coupled to a co-planar feed line [1]. Photon detection is achieved by measuring the change in quasi-particle density caused by the splitting of Cooper pairs in the superconducting resonant element. This change in quasi-particle density alters the kinetic inductance, and hence the resonant frequency of the resonant element. This arrangement requires the quasi-particles generated by photon absorption to be concentrated at positions of high current density in the resonator. This is usually achieved through antenna coupling or quasi-particle trapping. For these detectors to work at wavelengths shorter than around 500 μm where antenna coupling can introduce a significant loss of efficiency, then a direct absorption method needs to be considered. One solution to this problem is the Lumped Element KID (LEKID), which shows no current variation along its length and can be arranged into a photon absorbing area coupled to free space and therefore requiring no antennas or quasi-particle trapping. This paper outlines the relevant microwave theory of a LEKID, along with theoretical and measured performance for these devices.

Original language | English (US) |
---|---|

Pages (from-to) | 530-536 |

Number of pages | 7 |

Journal | Journal of Low Temperature Physics |

Volume | 151 |

Issue number | 1-2 PART 1 |

DOIs | |

State | Published - Apr 2008 |

Externally published | Yes |

### Fingerprint

### Keywords

- Kinetic inductance
- Lumped element

### ASJC Scopus subject areas

- Physics and Astronomy (miscellaneous)

### Cite this

*Journal of Low Temperature Physics*,

*151*(1-2 PART 1), 530-536. https://doi.org/10.1007/s10909-007-9685-2

**Lumped element kinetic inductance detectors.** / Doyle, Simon; Mauskopf, Philip; Naylon, J.; Porch, A.; Duncombe, C.

Research output: Contribution to journal › Article

*Journal of Low Temperature Physics*, vol. 151, no. 1-2 PART 1, pp. 530-536. https://doi.org/10.1007/s10909-007-9685-2

}

TY - JOUR

T1 - Lumped element kinetic inductance detectors

AU - Doyle, Simon

AU - Mauskopf, Philip

AU - Naylon, J.

AU - Porch, A.

AU - Duncombe, C.

PY - 2008/4

Y1 - 2008/4

N2 - Kinetic Inductance Detectors (KIDs) provide a promising solution to the problem of producing large format arrays of ultra sensitive detectors for astronomy. Traditionally KIDs have been constructed from superconducting quarter-wave resonant elements capacitively coupled to a co-planar feed line [1]. Photon detection is achieved by measuring the change in quasi-particle density caused by the splitting of Cooper pairs in the superconducting resonant element. This change in quasi-particle density alters the kinetic inductance, and hence the resonant frequency of the resonant element. This arrangement requires the quasi-particles generated by photon absorption to be concentrated at positions of high current density in the resonator. This is usually achieved through antenna coupling or quasi-particle trapping. For these detectors to work at wavelengths shorter than around 500 μm where antenna coupling can introduce a significant loss of efficiency, then a direct absorption method needs to be considered. One solution to this problem is the Lumped Element KID (LEKID), which shows no current variation along its length and can be arranged into a photon absorbing area coupled to free space and therefore requiring no antennas or quasi-particle trapping. This paper outlines the relevant microwave theory of a LEKID, along with theoretical and measured performance for these devices.

AB - Kinetic Inductance Detectors (KIDs) provide a promising solution to the problem of producing large format arrays of ultra sensitive detectors for astronomy. Traditionally KIDs have been constructed from superconducting quarter-wave resonant elements capacitively coupled to a co-planar feed line [1]. Photon detection is achieved by measuring the change in quasi-particle density caused by the splitting of Cooper pairs in the superconducting resonant element. This change in quasi-particle density alters the kinetic inductance, and hence the resonant frequency of the resonant element. This arrangement requires the quasi-particles generated by photon absorption to be concentrated at positions of high current density in the resonator. This is usually achieved through antenna coupling or quasi-particle trapping. For these detectors to work at wavelengths shorter than around 500 μm where antenna coupling can introduce a significant loss of efficiency, then a direct absorption method needs to be considered. One solution to this problem is the Lumped Element KID (LEKID), which shows no current variation along its length and can be arranged into a photon absorbing area coupled to free space and therefore requiring no antennas or quasi-particle trapping. This paper outlines the relevant microwave theory of a LEKID, along with theoretical and measured performance for these devices.

KW - Kinetic inductance

KW - Lumped element

UR - http://www.scopus.com/inward/record.url?scp=40649125007&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=40649125007&partnerID=8YFLogxK

U2 - 10.1007/s10909-007-9685-2

DO - 10.1007/s10909-007-9685-2

M3 - Article

AN - SCOPUS:40649125007

VL - 151

SP - 530

EP - 536

JO - Soviet Journal of Low Temperature Physics (English Translation of Fizika Nizkikh Temperatur)

JF - Soviet Journal of Low Temperature Physics (English Translation of Fizika Nizkikh Temperatur)

SN - 1063-777X

IS - 1-2 PART 1

ER -