Abstract: Disclosed are a device and methods for obtaining signals related to blood analytes and bone features by collecting spectra, such as fluorescence and Raman spectra, through the nail of a finger or toe. The invention additionally provides methods of modulating blood flow in a tissue of a subject.

Abstract: Disclosed is a method for obtaining feedback to drive a servo system for aligning and maintaining alignment in optical systems that bring light to an in vivo skin sample, for adjusting the focus of the optical system, and for adjusting the net depth of focus of the optical system within the in vivo system under characterization. These methods comprise adjusting the angle of incidence of electromagnetic radiation and/or providing a shielding lens to block scattered incident light, or otherwise limiting the field of view of the Raman scattered radiation collection system to exclude optical surfaces of the excitation delivery portion of the optical system. In one embodiment, the method comprises discriminating between Raman signals originating on outer portions of skin from signals originating from substances deeper within the skin or other tissues. In another embodiment, the invention provides a method for detecting skin abnormalities and for assessing the aging of skin and related tissues.

Abstract: Disclosed are a device and methods for obtaining signals related to blood analytes and bone features by collecting spectra, such as fluorescence and Raman spectra, through the nail of a finger or toe. The invention additionally provides methods of modulating blood flow in a tissue of a subject.

Abstract: Disclosed is a method for obtaining feedback to drive a servo system for aligning and maintaining alignment in optical systems that bring light to an in vivo skin sample, for adjusting the focus of the optical system, and for adjusting the net depth of focus of the optical system within the in vivo system under characterization. The invention additionally provides a method for obtaining feedback to drive a servo system for aligning and maintaining alignment in optical systems that collect light from an in vivo skin sample, and for adjusting the focus of the optical system. These methods comprise adjusting the angle of incidence of electromagnetic radiation and/or providing a shielding lens to block scattered incident light, or otherwise limiting the field of view of the Raman scattered radiation collection system to exclude optical surfaces of the excitation delivery portion of the optical system. Also provided is a method for identifying spectroscopic depth markers in tissues.

Abstract: Disclosed is a method for obtaining feedback to drive a servo system for aligning and maintaining alignment in optical systems that bring light to an in vivo skin sample, for adjusting the focus of the optical system, and for adjusting the net depth of focus of the optical system within the in vivo system under characterization. The invention additionally provides a method for obtaining feedback to drive a servo system for aligning and maintaining alignment in optical systems that collect light from an in vivo skin sample, and for adjusting the focus of the optical system. These methods comprise adjusting the angle of incidence of electromagnetic radiation and/or providing a shielding lens to block scattered incident light, or otherwise limiting the field of view of the Raman scattered radiation collection system to exclude optical surfaces of the excitation delivery portion of the optical system. Also provided is a method for identifying spectroscopic depth markers in tissues.