We have developed a new narrowband tunable filter to perform imaging spectroscopy of the solar chromosphere.
Using Liquid Crystal Variable Retarders (LCVRs) as the tuning elements for wavelength, wide-band polarizers
and super achromatic half-wave plates, it is possible to make high speed tuning (about 0.1Sec), to exclude
mechanical drives (and oil tank), and to cover a wide wavelength range (510-100nm). This filter builds up
with seven stages each consisting of a pair of calcites, LCVR, half-wave plates and linear polarizer. The full
width at half maximum (FWHM) of the filter transmission is about 0.025nm at 656.3nm.We demonstrate that
the concept of the universal tunable filter using the LCVR's as tuning elements is highly promising for future
application to space mission and ground based observations.