How to enable Highlighter

[askids]

hi,

Is there any setting that has to be enabled to allow highlighter to work? Currently, I am not getting the highlight section itself in the response. I am using ES 5.5.1 on windows 2012.

  GET individual/_search
{
  "query": {
    "match": {
      "last_Name": "tester"
    }
  },
  "highlight": {
    "pre_tags": [
      "<tag1>"
    ],
    "post_tags": [
      "</tag1>"
    ],
    "encoder": "html",
    "fields": {
      "last_Name": {}
    }
  }
}

In the response, I am not seeing any highlight section at all.

{
  "took": 1,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "failed": 0
  },
  "hits": {
    "total": 28,
    "max_score": 7.467892,
    "hits": [
      {
        "_index": "individual",
        "_type": "individual",
        "_id": "123",
        "_score": 7.467892,
        "_source": {
          "first_Name": "DUMMY1",
          "last_Name": "TESTER",
          "display_Name": "TESTER, DUMMY1"
        }
      },
      {
        "_index": "individual",
        "_type": "individual",
        "_id": "124",
        "_score": 7.467892,
        "_source": {
          "first_Name": "DUMMY2",
          "last_Name": "TESTER",

Please let me know if any setting at index or node level has to be enabled to make the highlighter to work.

Thanks!