A container for holding a sample and a system and method for a handheld
spectrometer using the container is disclosed. In one embodiment, the
container includes a vial with an optical window at the base of the vial.
A sample may be placed in the vial. A hollow plunger may be slidably
inserted into the vial which seals the gap between the plunger and the
walls of the vial. The plunger includes a filter element. When the
plunger is inserted into the vial, the sample is forced against the
optical window and the filter element vents liquid and/or gas that is in
the vial into the hollow plunger. A portable or handheld system for
detecting, for example, biothreat agents makes use of the container in
order to determine a spectrum of the sample. The optical window of the
container is preferably substantially transparent to photons illuminating
the sample and to photons produced due to the interaction of the
illuminating photons and the sample.