Optoacoustic determination of optical attenuation depth using interferometric detection.
We use a modified Mach-Zehnder interferometer to measure surface displacement resulting from the thermoelastic response of a target to the absorption of a short laser pulse with axial and temporal resolutions of 0.1 nm and 3 ns, respectively. These measurements are used in conjunction with a solution to the thermoelastic wave equation and a nonlinear optimization algorithm to extract optical attenuation depth. We demonstrate the ability to determine the effective optical attenuation depth of homogeneous targets with either diffuse or specular reflecting surfaces with a precision of <or=4% for attenuation depths spanning 0.1 to 2 mm.
Payne
Barry P
BP
Massachusetts Institute of Technology, Department of Mechanical Engineering, Cambridge, Massachusetts 02139, USA.
Venugopalan
Vasan
V
Mikić
Bora B
BB
Nishioka
Norman S
NS
D000042:Absorption; D000162:Acoustics / Q000295:instrumentation; D003238:Connective Tissue / Q000502:physiology* / Q000648:ultrastructure*; D004548:Elasticity; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D008857:Microscopy, Interference / Q000295:instrumentation* / Q000379:methods*; D019047:Phantoms, Imaging; D012542:Scattering, Radiation; D041622:Tomography, Optical / Q000295:instrumentation* / Q000379:methods*