Various oxidation states and location sites of chromium (Cr) in doped crystal have been known. Since the high sensitivity
of ligand field on chromium ions, these are attributable to a broadband emission. The wide broadband emission can
potentially be exploited in many ways. For instance, a Cr-doped broadband amplified spontaneous emission can improve
spatial resolution many times in optical coherence tomography (OCT) diagnostic instrumentation.
It is difficult to further extend the emission bandwidth of Cr in a single crystal, although a single crystal is generally
considered as the best host. Amorphous as a host, on the other hand, may potentially expand the bandwidth of emission
and accommodate higher doping concentration. However, a single crystal is beneficial to a specific valance state through
charge compensation technique.
To investigate chromium's full potential, both Cr-doped nano-crystalline embedded in an amorphous host and Cr-doped
glasses are proposed. The ultimate aims are capable of tailoring oxidation states, site symmetry and concentrations of Cr
doping. In the first stage, Cr:YAG-doped silica fiber will be studied as a part of our research scope.