Speckle, a factor reducing
image quality in
optical coherence tomography (“OCT”), can limit the ability to identify cellular structures that are important for the diagnosis of a variety of diseases. The present invention allows for an implementation of an angular compounding, angular compounding by
path length encoding (“ACPE”) for reducing speckle in OCT images. By averaging images obtained at different incident angles, with each image encoded by
path length, ACPE maintains high-speed
image acquisition and implements minimal modifications to OCT probe
optics. ACPE images obtained from tissue phantoms and
human skin in vivo demonstrate a qualitative improvement over traditional OCT and an increased
signal-to-
noise ratio (“SNR”). Accordingly, apparatus probe
catheter, and method are provided for irradiating a sample. In particular, an interferometer may forward forwarding an
electromagnetic radiation. In addition, a sample arm may receive the
electromagnetic radiation, and can include an arrangement which facilitates a production of at least two radiations from the
electromagnetic radiation so as to irradiate the sample. Such arrangement can be configured to
delay a first
radiation of the at least two radiations with respect to a second
radiation of the at least two radiations.