A gas cell for absorption spectroscopy, the gas cell comprising: a channel providing at least a passage from a first end to a second end, the channel comprising an inlet for receiving a gas sample from a gas source and an outlet for releasing the gas sample from the gas cell , the first end being substantially opposite from the second end; a first end component mounted to the channel at the first end, the first end component comprising a first extending member having a first member end mounted to the first end of the channel and a second member end extending inwardly within the channel ; a first optically transparent portion coupled to the first end so as to be positioned inwardly within the channel and positioned to receive an incident beam from a light source into the channel, the first optically transparent portion being mounted at the second member end of the first extending member ; a second end component mounted to the channel at the second end, the second end component comprising a second extending member having a first member end mounted to the second end of the channel and a second member end extending inwardly within the channel; and a second optically transparent portion coupled to the second end so as to be positioned inwardly within the channel , the second optically transparent portion being positioned to permit optical transmission into and out of the channel , the second optically transparent portion being mounted to the second member end of the second extending member ; characterized in that at least one of the first optically transparent portion and the second optically transparent portion comprises two optical layers, and a first optical layer of the two optical layers is positioned relative to a second optical layer of the two optical layers at an optical layer tilt angle . a channel providing at least a passage from a first end to a second end, the channel comprising an inlet for receiving a gas sample from a gas source and an outlet for releasing the gas sample from the gas cell , the first end being substantially opposite from the second end; a first end component mounted to the channel at the first end, the first end component comprising a first extending member having a first member end mounted to the first end of the channel and a second member end extending inwardly within the channel ; a first optically transparent portion coupled to the first end so as to be positioned inwardly within the channel and positioned to receive an incident beam from a light source into the channel, the first optically transparent portion being mounted at the second member end of the first extending member ; a second end component mounted to the channel at the second end, the second end component comprising a second extending member having a first member end mounted to the second end of the channel and a second member end extending inwardly within the channel; and a second optically transparent portion coupled to the second end so as to be positioned inwardly within the channel , the second optically transparent portion being positioned to permit optical transmission into and out of the channel , the second optically transparent portion being mounted to the second member end of the second extending member ; characterized in that at least one of the first optically transparent portion and the second optically transparent portion comprises two optical layers, and a first optical layer of the two optical layers is positioned relative to a second optical layer of the two optical layers at an optical layer tilt angle . <EOS>