Hideyoshi Horimai

Directional light scanning 3-D display

This paper presents a new Three-Dimensional display method, so called Directional Light Scanning 3D display. By using holographic screen as a beam scanner and high frame rate Spatial Light Modulator (SLM), this method requires only one SLM but can display high resolution 3D images, solving the usual problem of lack of resolution.

High density collinear holographic data storage system(Conference Presentation)

Collinear holography has been good candidate for a volumetric recording technology of holographic data storage system (HDSS), because of there are not only large storage capacities, high transfer rates, but also the unique configuration, in which the information and reference beams are modulated co-axially by the same spatial light modulator, as a new read/write method for HDSS are very promising. The optical pickup can be designed as small as DVDs, and can be placed on one side of the recording media (disc). In the disc structure, the preformatted reflective layer is used for the focus/tracking servo and reading address information, and a dichroic mirror layer is used for detecting holographic recording information without interfering with the preformatted information. A 2-dimensional digital page data format is used and the shift-multiplexing method is employed to increase recording density. As servo technologies are being introduced to control the objective lens to be maintained precisely to the disc in the recording and reconstructing process, a vibration isolator is no longer necessary. In this paper, we introduced the principle of the collinear holography and its media structure of disc. Some results of experimental and theoretical studies suggest that it is a very effective method. We also discussed some methods to increase the recording density and data transfer rates of collinear holography using phase modulated page data format.

Big Data Storage Solution: Collinear Holographic Data Storage System

In the big data era, the necessity for large capacity, high transfer rates and long-term data storage systems has been increased. But, the main storage media we rely on currently are magnetic technology, like hard disk drives (HDD) and tape, which life times are several years only. They cannot satisfy the demand of prolonged preservation. Optical discs based on the bit-by-bit method, such as CD, DVD and Blu-ray Disc, for storing sound, movies, photos and other digital contents are widely used in our daily life. The long-term life time is one of the properties. The optical disc should be a good candidate of data storage system for big data preservation. However, the recording density limitation of the bit recording method are looming on the horizon.

Multi-level data write/read by phase-locked collinear holography

New method called phase-locked collinear holography was proposed and its performance was demonstrated experimentally. In this method, each pixel data contains phase-modulated multi-level information. When readout, the phase level of each pixel is converted to the amplitude level applied by holographic interferometry to collinear holography. This method is based on phase interference between phase-modulated signal beam and reference-phase beam (phase-lock beam); both of beams are traveled through common optical path. Using the 32-levels phase-modulated data, i.e. 5 bits phase information contained in one pixel was written and retrieved with low phase error bit [%], which is sufficient for practical use. In this paper actual optical set up for this method and write/retrieve sequence was described. Additionally, over sampling phase shifting interferometry will be discussed at the conference in order to detect phase-modulated data pages directly.

Directional Light Scanning 3-D display

This paper presents a new type of three-dimensional (3D) display method, namely directional light scanning 3D display. By using holographic screen as a beam scanner, this method provides us high-resolution 3D images with a spatial light modulator.

Recording Material for Collinear Holographic Memory

ユビキタス社会の発展によりデータストレージにはさらなる記録容量と転送レートの向上が望まれているが, BDやHD DVDなどいわゆるbit-by-bit記録方式ではその能力がここ数年で限界に到達すると考えられている。そこで最近次世代メモリーとして脚光を浴びているコリニア方式ホログラフィックメモリー用光記録媒体について,記録の機構や構成成分,記録材料への要求特性や評価方法について,筆者らの研究例を通じて概説する。

Collinear holography with magneto-optic spatial light modulator

Spatial light modulators (SLMs) are key components of collinear holographic storage. Collinear holography utilizes coaxially aligned information and reference beams which are displayed simultaneously by a same SLM for writing process, and also employs reference beam for retrieving process. We developed magneto-optic spatial light modulators (MOSLMs) which have high-speed switching and applied them to transmission-type collinear holography. In this study, we investigate performance of collinear holography with magneto-optic spatial light modulator. The Bit error rate was 8.9×10-3 for single hologram. To examine the performance of shift-multiplexing, reconstructed image was disappeared after 3 μm shift. MOSLMs is suitable for collinear holography in terms of transfer rate especially.