TY - CONF

T1 - The mid-infrared swept laser

T2 - SPIE BiOS

AU - Childs, D.T.D.

AU - Hogg, R.A.

AU - Revin, D.G.

AU - Rehman, I.U.

AU - Cockburn, J.W.

AU - Matcher, S.J.

A2 - V.V., Tuchin

A2 - J.G., Fujimoto

A2 - J.A., Izatt

PY - 2015

Y1 - 2015

N2 - Near-infrared external cavity lasers with high tuning rates ("swept lasers") have come to dominate the field of near-infrared low-coherence imaging of biological tissues. Compared with time-domain OCT, swept-source OCT a) replaces slow mechanical scanning of a bulky reference mirror with much faster tuning of a laser cavity filter element and b) provides a ×N (N being the number of axial pixels per A-scan) speed advantage with no loss of SNR. We will argue that this striking speed advantage has not yet been fully exploited within biophotonics but will next make its effects felt in the mid-infrared. This transformation is likely to be driven by recent advances in external cavity quantum cascade lasers, which are the mid-IR counterpart to the OCT swept-source. These mid-IR sources are rapidly emerging in the area of infrared spectroscopy. By noting a direct analogy between time-domain OCT and Fourier Transform Infrared (FTIR) spectroscopy we show analytically and via simulations that the mid-IR swept laser can acquire an infrared spectrum ×N (N being the number of spectral data points) faster than an FTIR instrument, using identical detected flux levels and identical receiver noise. A prototype external cavity mid-IR swept laser is demonstrated, offering a comparatively low sweep rate of 400 Hz over 60 cm-1 with 2 cm-1 linewidth, but which provides evidence that sweep rates of over a 100 kHz should be readily achievable simply by speeding up the cavity tuning element. Translating the knowledge and experience gained in near-IR OCT into mid-IR source development may result in sources offering significant benefits in certain spectroscopic applications. © 2015 SPIE.

AB - Near-infrared external cavity lasers with high tuning rates ("swept lasers") have come to dominate the field of near-infrared low-coherence imaging of biological tissues. Compared with time-domain OCT, swept-source OCT a) replaces slow mechanical scanning of a bulky reference mirror with much faster tuning of a laser cavity filter element and b) provides a ×N (N being the number of axial pixels per A-scan) speed advantage with no loss of SNR. We will argue that this striking speed advantage has not yet been fully exploited within biophotonics but will next make its effects felt in the mid-infrared. This transformation is likely to be driven by recent advances in external cavity quantum cascade lasers, which are the mid-IR counterpart to the OCT swept-source. These mid-IR sources are rapidly emerging in the area of infrared spectroscopy. By noting a direct analogy between time-domain OCT and Fourier Transform Infrared (FTIR) spectroscopy we show analytically and via simulations that the mid-IR swept laser can acquire an infrared spectrum ×N (N being the number of spectral data points) faster than an FTIR instrument, using identical detected flux levels and identical receiver noise. A prototype external cavity mid-IR swept laser is demonstrated, offering a comparatively low sweep rate of 400 Hz over 60 cm-1 with 2 cm-1 linewidth, but which provides evidence that sweep rates of over a 100 kHz should be readily achievable simply by speeding up the cavity tuning element. Translating the knowledge and experience gained in near-IR OCT into mid-IR source development may result in sources offering significant benefits in certain spectroscopic applications. © 2015 SPIE.

KW - Fellgett advantage

KW - FTIR

KW - Infrared spectroscopy

KW - OCT

KW - Swept lasers

KW - Infrared devices

KW - Laser mirrors

KW - Optical tomography

KW - Photonics

KW - Quantum cascade lasers

KW - Signal to noise ratio

KW - Time domain analysis

KW - Tissue

KW - Tomography

KW - External cavity lasers

KW - Knowledge and experience

KW - Low coherence imaging

KW - Spectroscopic application

KW - Fourier transform infrared spectroscopy

U2 - 10.1117/12.2081872

DO - 10.1117/12.2081872

M3 - Conference paper

Y2 - 2 March 2015

ER -