Highly sensitive photonic crystal fiber based absorption spectroscopy

We have reported a highly sensitive evanescent field based absorption spectroscopy using an optimized structure of PCF with defected-core. The absorption sensitivity up to 10.8 mol−1 has been achieved which is six times improvement compared with the previous reported 1.6 mol−1 sensitivity in a defected-core PCF. Moreover, this structure can achieve a twice higher sensitivity compared with commercial spectrophotometer. Excellent linear relationship has been obtained between absorption and aqueous sample concentrations which suggested that the PCF is a satisfactory candidature as an absorption spectroscopy for off-chip or on-chip analyte quantitation.