  This study developed handheld and low-cost digital holographic microscopy
(DHM) by adopting an in-line type hologram, a webcam, a high power RGB light
emitting diode (LED), and a pinhole. It cost less than 20,000 yen
(approximately 250 US dollars at 80 yen/dollar), and was approximately 120 mm x
80 mm x 55 mm in size. In addition, by adjusting the recording-distance of a
hologram, the lateral resolution power at the most suitable distance was 17.5
um. Furthermore, this DHM was developed for use in open source libraries, and
is therefore low-cost and can be easily developed by anyone. In this research,
it is the feature to cut down cost and size and to improve the lateral
resolution power further rather than existing reports. This DHM will be a
useful application in fieldwork, education, and so forth.
