How to build an optical filter with an atomic vapor cell

The nature of atomic vapors, their natural alignment with interatomic transitions, and their ease of use make them highly suited for spectrally narrow-banded optical filters. Atomic filters come in two flavors: a filter based on the absorption of light by the Doppler broadened atomic vapor, i.e. a notch filter, and a bandpass filter based on the transmission of resonant light caused by the Faraday effect. The notch filter uses the absorption of resonant photons to filter out a small spectral band around the atomic transition. The off-resonant part of the spectrum is fully transmitted. Atomic vapors based on the Faraday effect allow for suppression of the detuned spectral fraction. Transmission of light originates from the magnetically induced rotation of linear polarized light close to an atomic resonance. This filter constellation allows selective acceptance of specific light frequencies. In this manuscript, we discuss these two types of filters and elucidate the specialties of atomic line filters. We also present a practical guide on building such filter setups from scratch and discuss an approach to achieve an almost perfect atomic spectrum backed by theoretical calculations

Einsatz von Polyelektrolyt-Multischichten für das temporäre Waferbonden

Das Bonden dient zum Verbinden von Siliziumwafern und ist in der Mikrosystem- und Halbleitertechnik häufig genutztes Verfahren, aber infolge ständig steigender technischer Anforderungen ist das Handling von großflächigen und ultradünnen Wafern erschwert. Das temporäre Waferbonden bietet die Möglichkeit, den Prozesswafer für notwendige Bearbeitungsschritte auf einem Trägerwafer mittels einer Zwischenschicht zu fixieren und diesen nach Abschluss der Prozessschritte wieder zu lösen. In der vorliegenden Arbeit werden Polyelektrolyt-Multischichten (PEM) als Zwischenschicht zwischen den Siliziumwafern eingesetzt. Das Bondverhalten wird anhand unterschiedlicher PEM-Kombinationen evaluiert, wobei der Fokus der experimentellen Untersuchungen auf der Bestimmung der Bondstärke liegt. Der verwendete Klingentest bietet die Möglichkeit, die Bondenergie in situ in Abhängigkeit der Temperatur zu bestimmen. Ein neuer, hier erstmals untersuchter Ansatz zum temporären Bonden mit Polyelektrolyt-Multischichten basiert auf ihrem anaeroben photokatalytischen Abbau durch Bestrahlung mit UV-Licht

How to build an optical filter with an atomic vapor cell

The nature of atomic vapors, their natural alignment with interatomic transitions, and their ease of use make them highly suited for spectrally narrow-banded optical filters. Atomic filters come in two flavors: a filter based on the absorption of light by the Doppler broadened atomic vapor, i.e. a notch filter, and a bandpass filter based on the transmission of resonant light caused by the Faraday effect. The notch filter uses the absorption of resonant photons to filter out a small spectral band around the atomic transition. The off-resonant part of the spectrum is fully transmitted. Atomic vapors based on the Faraday effect allow for suppression of the detuned spectral fraction. Transmission of light originates from the magnetically induced rotation of linear polarized light close to an atomic resonance. This filter constellation allows selective acceptance of specific light frequencies. In this manuscript, we discuss these two types of filters and elucidate the specialties of atomic line filters. We also present a practical guide on building such filter setups from scratch and discuss an approach to achieve an almost perfect atomic spectrum backed by theoretical calculations