Spectral properties of the indicators and optical components.

<p>Transmission and normalized intensity spectra of the optical filters and the Pd-TFPP dye. A 405 nm LED is used to excite the dye and a DT Blue interference filter (the shown spectrum is the transmission at a 45° angle) is used to ensure that no excitation light is in the relevant detection region. A stack of Bright Red and RG 630 color filters combined with a Calflex X interference filter form a band pass for the interesting emission region. The Bright Red filter is used to minimize fluorescence inherent to the RG 630 color filter.