We realized a long-scanning-range and high-resolution interferometry in a time-domain full-field microscopic scheme by adopting a simple configuration. A reference mirror was synchronously scanned with an objective lens, which was installed in a common path, to prevent lateral resolution degradation due to defocus at the mirror. High axial resolution was obtained using a broadband supercontinuum (SC) generated by a 1.55 µm pump. The SC was generated by propagating a femtosecond pulse at 1.55 µm through a highly nonlinear dispersion shifted fiber with a small dispersion slope. We designed and constructed an interferometer carefully to utilize the entire bandwidth. The broad bandwidth of the interferometer achieved an axial resolution of 2.50 µm in air. The synchronous scanning maintained a lateral resolution longer than 1 mm. The system successfully yielded a cross-sectional image of two layers of scotch tape along the 400-µm-depth and 90-nm-step surface profiles.

The multi-gigahertz frequency comb-based interferometer exhibits only the interference amplitude peak without the phase fringes, which can produce a rapid axial scan for full-field profilometry and tomography. Despite huge technical advantages, there remain problems that the interference intensity undulations occurred depending on the interference phase. To avoid such problems, we propose a compensation technique of the interference signals using two frequency combs with slightly varied center wavelengths. The compensated full-field surface profile measurements of cover glass and onion skin were demonstrated experimentally to verify the advantages of the proposed method.

A multi-gigahertz frequency comb (MGFC)-based interferometer was developed for profilometry and tomography using a frequency variable supercontinuum (SC). The comparatively flattened and broadened SC light source with variable multi-gigahertz interval frequency was developed using an optical pulse synthesizer and highly nonlinear dispersion flattened fiber. The generated SC provided a stable interference output with a full width half maximum of 19 μm during interval frequency sweeping of over 400 MHz. We experimentally confirmed that the interference signal exhibited an envelope-only waveform without fringes, which enabled the drastic reduction of the sampling points resulting in high speed measurement. A full-field 3-D image with 320 × 256 × 300 pixels was acquired with a measurement time of only 10 seconds. It was demonstrated that the MGFC-based interferometer with the novel SC light source has the potential for application in a high speed full-field 3-D metrology.

We propose a new technique for stable interferometric measurement by calculating interferograms from obtained signals using two supercontinua whose center wavelengths are slightly different. We successfully obtained a thickness profile of a glass plate.

We have constructed a high-resolution interferometer with a broadband supercontinuum light source. The broadband characteristic of the interferometer achieved axial resolution of 2.16 μm at a center wavelength of 1550 nm.