Jan Schmidt - Academia.edu (original) (raw)

Papers by Jan Schmidt

Applied Physics Letters, 2000

Excited state radiative lifetime measurements are made on porous silicon as a function of excitat... more Excited state radiative lifetime measurements are made on porous silicon as a function of excitation wavelength and excitation intensity. The results indicate that a simple quantum confinement model for the light absorption and emission mechanism is not suitable. We ...

International Symposium on Photoelectronic Detection and Imaging 2011: Sensor and Micromachined Optical Device Technologies, 2011

MOEMS Display and Imaging Systems III, 2005

ABSTRACT High reflecting low-stress optical coatings for the next-generation of micro mechanical ... more ABSTRACT High reflecting low-stress optical coatings for the next-generation of micro mechanical mirrors have been developed. The optimized metal systems are applicable from VUV and DUV down to the UV and VIS spectral region and can be integrated in the technology of MOEMS, such as spatial light modulators (SLM) and micro scanning mirrors. This optimized metal designs enable to reconcile high optical performances with adequate mechanical properties and convenient CMOS compatibility. Currently, micro-mirror arrays with enhanced highly reflective coatings for DUV (lambda = 193 nm) and VUV (lambda = 157 nm) exist as prototypes.

MOEMS Display and Imaging Systems III, 2005

ABSTRACT This paper addresses different highly reflective optical coatings on micro scanning mirr... more ABSTRACT This paper addresses different highly reflective optical coatings on micro scanning mirrors (MSM) for applications in the NIR-spectral region to enable new applications like laser marking and material treatment at high optical power density. In the case of MSM with an unprotected Al coating, the absorption limits the maximal power density because of induced heating. The damage threshold for unprotected Al coatings was investigated. In addition highly reflective enhanced metallic and dielectric multilayer coatings for the NIR have been developed and characterized. These coatings resolve the problems of unprotected aluminum coatings related to NIR absorption and the resulting limitation of applicable laser power density. The coatings ensure a high reflectance even in corrosive environments. Enhanced metallic broadband reflectors reach a reflectivity of 98.7% at 1064 nm whereas narrow-band dielectric multilayer coatings reach a reflectivity of 99.7% at 1064 nm.

Advances in Optical Thin Films II, 2005

This paper deals with vacuum UV optical coatings for micro mirrors applications. High reflecting ... more This paper deals with vacuum UV optical coatings for micro mirrors applications. High reflecting low-stress optical coatings for the next-generation of micro mechanical mirrors have been developed. The optimized metal systems are applicable for the VUV spectral region and can be integrated in the technology of MOEMS, such as spatial light modulators (SLM) and micro scanning mirrors.

Advances in Optical Thin Films II, 2005

ABSTRACT This paper addresses different highly reflective optical coatings on micro scanning mirr... more ABSTRACT This paper addresses different highly reflective optical coatings on micro scanning mirrors (MSM) for applications in the NIR-VIS-UV-spectral region to enable new applications at high optical power density like laser marking and material treatment. In the common case of MSM with an unprotected Al coating, the absorption limits the maximal power density because of induced heating. In contrast to macroscopic optics HR-micro mirror coatings have to guarantee additional demands like low-stress and CMOS compatibility. Hence, to enable novel high power applications of MSM in the NIR-VIS-UV spectral region highly reflective low-stress coatings have been developed according to a triple strategy: (a) broadband metallic reflectors, (b) dielectric multilayers and (c) enhanced hybrid coatings. For Au and Ag based NIR-coatings an excellent mirror planarity and a reflectance around 99 % (@ 1064 nm) have been achieved, whereas dielectric coatings reached 99.7 % for a (LH)4 design and thinner low-stress hybrid NIR-coatings reached up to 99.8% enabling an improved mirror planarity and excellent laser damage threshold. For the VIS and UV spectral region enhanced hybrid HR-coatings have been favored, because they enable high reflectance of up to 99.7 % @ 633 nm or 98.8 % @ 308 nm in combination with low stress, high mirror planarity and CMOS compatibility.

MOEMS Display, Imaging, and Miniaturized Microsystems IV, 2006

ABSTRACT This paper addresses different highly reflective optical coatings on micro scanning mirr... more ABSTRACT This paper addresses different highly reflective optical coatings on micro scanning mirrors (MSM) for applications in the NIR-VIS-UV- spectral region to enable new applications at high optical power density like laser marking and material treatment. In the common case of MSM with an unprotected Al coating, the absorption limits the maximal power density because of induced heating. In contrast to macroscopic optics HR-micro mirror coatings have to guarantee additional demands like low-stress and CMOS compatibility. Hence, to enable novel high power applications of MSM in the NIR-VIS-UV spectral region highly reflective low-stress coatings have been developed according to a triple strategy: (a) broadband metallic reflectors, (b) dielectric multilayers and (c) enhanced hybrid coatings. For Au and Ag based NIR-coatings an excellent mirror planarity and a reflectance around 99 % (@ 1064 nm) have been achieved, whereas dielectric coatings reached 99.7 % for a (LH)4 design and thinner low-stress hybrid NIR-coatings reached up to 99.8 % enabling an improved mirror planarity and excellent laser damage threshold. For the VIS and UV spectral region enhanced hybrid HR-coatings have been favored, because they enable high reflectance of up to 99.7 % @ 633 nm or 98.8 % @ 308 nm in combination with low stress, high mirror planarity and CMOS compatibility.

Smart Sensors, Actuators, and MEMS IV, 2009

Aluminum nitride (AlN) is a promising piezoelectric material suitable for full CMOS compatible ME... more Aluminum nitride (AlN) is a promising piezoelectric material suitable for full CMOS compatible MEMS processes. Due to the transversal inverse piezoelectric effect the use of AlN enables quasistatic deformable mirrors by actively coupling lateral strain in micro machined membranes. In this work a fast and reliable way for reactive magnetron rf-sputtered aluminum nitride thin films with piezoelectric properties is shown.

Applied Physics Letters, 2000

Excited state radiative lifetime measurements are made on porous silicon as a function of excitat... more Excited state radiative lifetime measurements are made on porous silicon as a function of excitation wavelength and excitation intensity. The results indicate that a simple quantum confinement model for the light absorption and emission mechanism is not suitable. We ...

International Symposium on Photoelectronic Detection and Imaging 2011: Sensor and Micromachined Optical Device Technologies, 2011

MOEMS Display and Imaging Systems III, 2005

ABSTRACT High reflecting low-stress optical coatings for the next-generation of micro mechanical ... more ABSTRACT High reflecting low-stress optical coatings for the next-generation of micro mechanical mirrors have been developed. The optimized metal systems are applicable from VUV and DUV down to the UV and VIS spectral region and can be integrated in the technology of MOEMS, such as spatial light modulators (SLM) and micro scanning mirrors. This optimized metal designs enable to reconcile high optical performances with adequate mechanical properties and convenient CMOS compatibility. Currently, micro-mirror arrays with enhanced highly reflective coatings for DUV (lambda = 193 nm) and VUV (lambda = 157 nm) exist as prototypes.

MOEMS Display and Imaging Systems III, 2005

ABSTRACT This paper addresses different highly reflective optical coatings on micro scanning mirr... more ABSTRACT This paper addresses different highly reflective optical coatings on micro scanning mirrors (MSM) for applications in the NIR-spectral region to enable new applications like laser marking and material treatment at high optical power density. In the case of MSM with an unprotected Al coating, the absorption limits the maximal power density because of induced heating. The damage threshold for unprotected Al coatings was investigated. In addition highly reflective enhanced metallic and dielectric multilayer coatings for the NIR have been developed and characterized. These coatings resolve the problems of unprotected aluminum coatings related to NIR absorption and the resulting limitation of applicable laser power density. The coatings ensure a high reflectance even in corrosive environments. Enhanced metallic broadband reflectors reach a reflectivity of 98.7% at 1064 nm whereas narrow-band dielectric multilayer coatings reach a reflectivity of 99.7% at 1064 nm.

Advances in Optical Thin Films II, 2005

This paper deals with vacuum UV optical coatings for micro mirrors applications. High reflecting ... more This paper deals with vacuum UV optical coatings for micro mirrors applications. High reflecting low-stress optical coatings for the next-generation of micro mechanical mirrors have been developed. The optimized metal systems are applicable for the VUV spectral region and can be integrated in the technology of MOEMS, such as spatial light modulators (SLM) and micro scanning mirrors.

Advances in Optical Thin Films II, 2005

ABSTRACT This paper addresses different highly reflective optical coatings on micro scanning mirr... more ABSTRACT This paper addresses different highly reflective optical coatings on micro scanning mirrors (MSM) for applications in the NIR-VIS-UV-spectral region to enable new applications at high optical power density like laser marking and material treatment. In the common case of MSM with an unprotected Al coating, the absorption limits the maximal power density because of induced heating. In contrast to macroscopic optics HR-micro mirror coatings have to guarantee additional demands like low-stress and CMOS compatibility. Hence, to enable novel high power applications of MSM in the NIR-VIS-UV spectral region highly reflective low-stress coatings have been developed according to a triple strategy: (a) broadband metallic reflectors, (b) dielectric multilayers and (c) enhanced hybrid coatings. For Au and Ag based NIR-coatings an excellent mirror planarity and a reflectance around 99 % (@ 1064 nm) have been achieved, whereas dielectric coatings reached 99.7 % for a (LH)4 design and thinner low-stress hybrid NIR-coatings reached up to 99.8% enabling an improved mirror planarity and excellent laser damage threshold. For the VIS and UV spectral region enhanced hybrid HR-coatings have been favored, because they enable high reflectance of up to 99.7 % @ 633 nm or 98.8 % @ 308 nm in combination with low stress, high mirror planarity and CMOS compatibility.

MOEMS Display, Imaging, and Miniaturized Microsystems IV, 2006

ABSTRACT This paper addresses different highly reflective optical coatings on micro scanning mirr... more ABSTRACT This paper addresses different highly reflective optical coatings on micro scanning mirrors (MSM) for applications in the NIR-VIS-UV- spectral region to enable new applications at high optical power density like laser marking and material treatment. In the common case of MSM with an unprotected Al coating, the absorption limits the maximal power density because of induced heating. In contrast to macroscopic optics HR-micro mirror coatings have to guarantee additional demands like low-stress and CMOS compatibility. Hence, to enable novel high power applications of MSM in the NIR-VIS-UV spectral region highly reflective low-stress coatings have been developed according to a triple strategy: (a) broadband metallic reflectors, (b) dielectric multilayers and (c) enhanced hybrid coatings. For Au and Ag based NIR-coatings an excellent mirror planarity and a reflectance around 99 % (@ 1064 nm) have been achieved, whereas dielectric coatings reached 99.7 % for a (LH)4 design and thinner low-stress hybrid NIR-coatings reached up to 99.8 % enabling an improved mirror planarity and excellent laser damage threshold. For the VIS and UV spectral region enhanced hybrid HR-coatings have been favored, because they enable high reflectance of up to 99.7 % @ 633 nm or 98.8 % @ 308 nm in combination with low stress, high mirror planarity and CMOS compatibility.

Smart Sensors, Actuators, and MEMS IV, 2009

Aluminum nitride (AlN) is a promising piezoelectric material suitable for full CMOS compatible ME... more Aluminum nitride (AlN) is a promising piezoelectric material suitable for full CMOS compatible MEMS processes. Due to the transversal inverse piezoelectric effect the use of AlN enables quasistatic deformable mirrors by actively coupling lateral strain in micro machined membranes. In this work a fast and reliable way for reactive magnetron rf-sputtered aluminum nitride thin films with piezoelectric properties is shown.