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Finesse and sensitivity gain in cavity-enhanced absorption spectroscopy of biomolecules in solution

McGarvey, Timothy and Conjusteau, André and Mabuchi, Hideo (2006) Finesse and sensitivity gain in cavity-enhanced absorption spectroscopy of biomolecules in solution. Optics Express, 14 (22). pp. 10441-10451. ISSN 1094-4087.

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We describe a ‘wet mirror’ apparatus for cw cavity-enhanced absorption measurements with Bacteriochlorophyll a (BChla) in solution and show that it achieves the full sensitivity gain (≈ 2.3×10^4) afforded by the finesse (3.4 × 10^4) and loss distribution of our optical resonator. This result provides an important proof-of-principle demonstration for solution-phase cavity-enhanced spectroscopy; straightforward extrapolation to a system with state-of-the-art low-loss mirrors and shot-noise-limited performance indicates that single molecule sensitivity in liquids is within reach of current technology. With the probe laser locked to the cavity resonance, our instrument achieves a sensitivity ≈3.4×10^−8/√Hz (for a sample of length 1.75 mm) with 100 kHz bandwidth and can reliably detect sub-nM concentrations of BChla with 1 ms integration time.

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Additional Information:© 2006 Optical Society of America Received 5 September 2006; revised 12 October 2006; accepted 20 October 2006; published October 30, 2006 We thank Michael Armen for invaluable technical assistance, as well as Dirk Englund, Orkun Aiken and Muhammed Yildirim for contributions to early stages of this work. This research was supported by the National Science Foundation and the W. M. Keck Foundation.
Issue or Number:22
Record Number:CaltechAUTHORS:MCGoe06
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:6376
Deposited By: Archive Administrator
Deposited On:05 Dec 2006
Last Modified:02 Oct 2019 23:32

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