A multimodal imaging system has been developed for tooth tissue imaging. This imaging system is designed to obtain
one or more two-dimensional images of the tooth tissue, and those two-dimensional images are rendered with
advanced algorithms to provide a high-contrast image. This system combines polarized reflectance imaging,
fluorescence imaging, and optical coherence tomography (OCT) imaging. The imaging system design, as well as
some experimental results, will be discussed in the presentation.
Dental caries is a disease in which minerals of the tooth are dissolved by surrounding bacterial plaques. A caries
process present for some time may result in a caries lesion. However, if it is detected early enough, the dentist and
dental professionals can implement measures to reverse and control caries. Several optical, nonionized methods have
been investigated and used to detect dental caries in early stages. However, there is not a method that can singly detect
the caries process with both high sensitivity and high specificity. In this paper, we present a multimodal imaging
system that combines visible reflectance, fluorescence, and Optical Coherence Tomography (OCT) imaging. This
imaging system is designed to obtain one or more two-dimensional images of the tooth (reflectance and fluorescence
images) and a three-dimensional OCT image providing depth and size information of the caries. The combination of
two- and three-dimensional images of the tooth has the potential for highly sensitive and specific detection of dental
We show theoretically and experimentally that a simple modification of the dynamic spectrogram may be used to characterize a stochastic ensemble of ultrashort optical pulses. The method makes use of the temporal analysis of spectral components to measure an intuitive spectrogram of the ensemble using a low order nonlinear technique. Pulse-shape reconstruction is demonstrated via an iterative inversion algorithm for an ensemble of identical input pulses. For pulses that are not identical, we measure for the first time a representation of the two-time correlation function of the pulsed field, using a non-iterative decorrelation procedure.
We discuss the method of time-resolved spectral phase measurement (TRSPM) as a technique for complete characterization of the electric field of a short optical pulse. Several phase retrieval algorithms, both deterministic and iterative, are compared.
We formulate some general conditions concerning the applicability of linear interferometers to the measurement of the amplitude and phase of short optical pulses. In particular it is shown that any system that utilizes an integrating detector must also consist of time nonstationary filters. Two novel schemes that meet this criterion are illustrated.
The amplitude and phase of ultrashort optical pulses generated by modelocked lasers yield information about the physical mechanisms that shape the pulse inside the laser. The form of the electric field of pulses with a duration of several tens of femtoseconds can only be retrieved through indirect diagnostic techniques, however. A number of protocols for determining the pulse field envelope have been developed in the past several years and, in this paper, we discuss the application of two pulse measurement techniques, including a novel linear interferometric method, to the measurement of the pulses from a colliding pulse modelocked (CPM) dye laser and a self-modelocked Ti:Sapphire laser.