Single-layer flexible touch sensor that is designed for the indium-tin-oxide (ITO)-free, bendable, durable, multi-sensible, and single layer transparent touch sensor was developed via a low-cost and one-step laser-induced fabrication technology. To this end, an entirely novel approach involving material, device structure, and even fabrication method was adopted. Conventional metal oxides based multilayer touch structure was substituted by the single layer structure composed of integrated silver wire networks of sensors and bezel interconnections. This structure is concurrently fabricated on a glass substitutive plastic film via the laser-induced fabrication method using the low-cost organometallic/nanoparticle hybrid complex. In addition, this study addresses practical solutions to heterochromia and interference problem with a color display unit. As a result, a practical touch sensor is successfully demonstrated through resolving the heterochromia and interference problems with color display unit. This study could provide the breakthrough for early realization of wearable device.

We report a time-domain method of stabilizing the carrier-envelope phase (CEP) of femtosecond pulses. Temporal variations of the pulse envelope and the carrier electric-field phase were separately detected with the aid of intensity cross-correlation and interferometric cross-correlation. These detected signals were used to stabilize the CEP; the resulting 50-fold improvement in the fractional stability of the carrier-envelop-offset frequency was evaluated as 1.2 × 10(-11) at 0.1 second averaging periods and 1.7 × 10(-9) at 80 seconds, corresponding to a carrier envelope phase noise of 75 microradians and 10 milliradians, respectively. This method can be realized with a low pulse energy of ~10 pJ and does not require subsequent power amplification or spectral broadening. The high efficiency and short-term stability of this method can facilitate the use of femtosecond lasers in the field of industrial surface measurements, telecommunications, and space sciences.

We describe an all-pass fiber resonator with active phase-locking capability for accurate multiplication of the repetition rate of femtosecond light pulses. The cavity length of the resonator is precisely controlled using the Pounder-Drever-Hall phase-locking technique so that the repetition rate is multiplied in stabilization to the Rb atomic clock. Our test result proves the proposed phase-locking scheme is an effective means of generating higher repetition rate pulses with no significant power loss while providing a high degree of long-term stability.

A heterodyne interference lithography method using two slightly different wavelengths for one-step multi-scale fabrication of micro/nano hybrid structures is presented. This method has been used to locally fabricate one- and two-dimensional periodical sub-wavelength nanopatterns with a spatial periodicity of several micrometers. Furthermore, multilayered nanostructures with different layer compositions were fabricated by simply controlling the intensity ratio of the two wavelengths. As a result, this method can cost-effectively maximize the degree of freedom of the interference lithography method. The heterodyne interference lithography method can potentially be used in the fabrication of unconventional bio-mimetically engineered surfaces as well as heterocomplexed optics.

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