A surface enhanced Raman scattering, SERS, sensor (220,320) comprising: a substrate; nano fingers, each comprising a bendable pillar supporting a metal tip, wherein each pillar is formed from a polymer having a glass transition temperature; the SERS sensor comprising: an electrically conductive layer having a first portion spaced from a second portion by a gap; an electrically resistive layer (250, 350) formed on the substrate and in contact with and extending between the first portion and the second portion of the electrically conductive layer to form an electrically resistive bridge across the gap, wherein the nano fingers extend upward from the bridge, wherein the bridge is configured to heat the nano fingers in response to electrical current flowing across the bridge from the first portion to the second portion; a housing secured over the nanofingers to form a chamber about the nano fingers to contain a sample fluid, the bridge underlying the chamber; a pulse voltage supply electrically connected to the first portion; a controller to control the pulse voltage supply so as to supply current across the electrically resistive bridge; a temperature sensor to sense a temperature of an interior of the chamber; wherein the controller controls the pulse voltage supply to heat each pillar to a temperature of at least the glass transition temperature; wherein the controller is configured to receive sensed feedback regarding the temperature of the interior of the chamber from the temperature sensor, and in response, adjust a duration or characteristic of electrical pulses supplied by the pulse voltage supply. a substrate; nano fingers, each comprising a bendable pillar supporting a metal tip, wherein each pillar is formed from a polymer having a glass transition temperature; the SERS sensor comprising: an electrically conductive layer having a first portion spaced from a second portion by a gap; an electrically resistive layer (250, 350) formed on the substrate and in contact with and extending between the first portion and the second portion of the electrically conductive layer to form an electrically resistive bridge across the gap, wherein the nano fingers extend upward from the bridge, wherein the bridge is configured to heat the nano fingers in response to electrical current flowing across the bridge from the first portion to the second portion; a housing secured over the nanofingers to form a chamber about the nano fingers to contain a sample fluid, the bridge underlying the chamber; a pulse voltage supply electrically connected to the first portion; a controller to control the pulse voltage supply so as to supply current across the electrically resistive bridge; a temperature sensor to sense a temperature of an interior of the chamber; wherein the controller controls the pulse voltage supply to heat each pillar to a temperature of at least the glass transition temperature; wherein the controller is configured to receive sensed feedback regarding the temperature of the interior of the chamber from the temperature sensor, and in response, adjust a duration or characteristic of electrical pulses supplied by the pulse voltage supply. an electrically conductive layer having a first portion spaced from a second portion by a gap; an electrically resistive layer (250, 350) formed on the substrate and in contact with and extending between the first portion and the second portion of the electrically conductive layer to form an electrically resistive bridge across the gap, wherein the nano fingers extend upward from the bridge, wherein the bridge is configured to heat the nano fingers in response to electrical current flowing across the bridge from the first portion to the second portion; a housing secured over the nanofingers to form a chamber about the nano fingers to contain a sample fluid, the bridge underlying the chamber; a pulse voltage supply electrically connected to the first portion; a controller to control the pulse voltage supply so as to supply current across the electrically resistive bridge; a temperature sensor to sense a temperature of an interior of the chamber; wherein the controller controls the pulse voltage supply to heat each pillar to a temperature of at least the glass transition temperature; wherein the controller is configured to receive sensed feedback regarding the temperature of the interior of the chamber from the temperature sensor, and in response, adjust a duration or characteristic of electrical pulses supplied by the pulse voltage supply.